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  • ROracle support for TimesTen In-Memory Database

    - by Sherry LaMonica
    Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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  • Developing Schema Compare for Oracle (Part 6): 9i Query Performance

    - by Simon Cooper
    All throughout the EAP and beta versions of Schema Compare for Oracle, our main request was support for Oracle 9i. After releasing version 1.0 with support for 10g and 11g, our next step was then to get version 1.1 of SCfO out with support for 9i. However, there were some significant problems that we had to overcome first. This post will concentrate on query execution time. When we first tested SCfO on a 9i server, after accounting for various changes to the data dictionary, we found that database registration was taking a long time. And I mean a looooooong time. The same database that on 10g or 11g would take a couple of minutes to register would be taking upwards of 30 mins on 9i. Obviously, this is not ideal, so a poke around the query execution plans was required. As an example, let's take the table population query - the one that reads ALL_TABLES and joins it with a few other dictionary views to get us back our list of tables. On 10g, this query takes 5.6 seconds. On 9i, it takes 89.47 seconds. The difference in execution plan is even more dramatic - here's the (edited) execution plan on 10g: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 108K| 939 || 1 | SORT ORDER BY | | 108K| 939 || 2 | NESTED LOOPS OUTER | | 108K| 938 ||* 3 | HASH JOIN RIGHT OUTER | | 103K| 762 || 4 | VIEW | ALL_EXTERNAL_LOCATIONS | 2058 | 3 ||* 20 | HASH JOIN RIGHT OUTER | | 73472 | 759 || 21 | VIEW | ALL_EXTERNAL_TABLES | 2097 | 3 ||* 34 | HASH JOIN RIGHT OUTER | | 39920 | 755 || 35 | VIEW | ALL_MVIEWS | 51 | 7 || 58 | NESTED LOOPS OUTER | | 39104 | 748 || 59 | VIEW | ALL_TABLES | 6704 | 668 || 89 | VIEW PUSHED PREDICATE | ALL_TAB_COMMENTS | 2025 | 5 || 106 | VIEW | ALL_PART_TABLES | 277 | 11 |------------------------------------------------------------------------------- And the same query on 9i: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 16P| 55G|| 1 | SORT ORDER BY | | 16P| 55G|| 2 | NESTED LOOPS OUTER | | 16P| 862M|| 3 | NESTED LOOPS OUTER | | 5251G| 992K|| 4 | NESTED LOOPS OUTER | | 4243M| 2578 || 5 | NESTED LOOPS OUTER | | 2669K| 1440 ||* 6 | HASH JOIN OUTER | | 398K| 302 || 7 | VIEW | ALL_TABLES | 342K| 276 || 29 | VIEW | ALL_MVIEWS | 51 | 20 ||* 50 | VIEW PUSHED PREDICATE | ALL_TAB_COMMENTS | 2043 | ||* 66 | VIEW PUSHED PREDICATE | ALL_EXTERNAL_TABLES | 1777K| ||* 80 | VIEW PUSHED PREDICATE | ALL_EXTERNAL_LOCATIONS | 1744K| ||* 96 | VIEW | ALL_PART_TABLES | 852K| |------------------------------------------------------------------------------- Have a look at the cost column. 10g's overall query cost is 939, and 9i is 55,000,000,000 (or more precisely, 55,496,472,769). It's also having to process far more data. What on earth could be causing this huge difference in query cost? After trawling through the '10g New Features' documentation, we found item 1.9.2.21. Before 10g, Oracle advised that you do not collect statistics on data dictionary objects. From 10g, it advised that you do collect statistics on the data dictionary; for our queries, Oracle therefore knows what sort of data is in the dictionary tables, and so can generate an efficient execution plan. On 9i, no statistics are present on the system tables, so Oracle has to use the Rule Based Optimizer, which turns most LEFT JOINs into nested loops. If we force 9i to use hash joins, like 10g, we get a much better plan: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 7587K| 3704 || 1 | SORT ORDER BY | | 7587K| 3704 ||* 2 | HASH JOIN OUTER | | 7587K| 822 ||* 3 | HASH JOIN OUTER | | 5262K| 616 ||* 4 | HASH JOIN OUTER | | 2980K| 465 ||* 5 | HASH JOIN OUTER | | 710K| 432 ||* 6 | HASH JOIN OUTER | | 398K| 302 || 7 | VIEW | ALL_TABLES | 342K| 276 || 29 | VIEW | ALL_MVIEWS | 51 | 20 || 50 | VIEW | ALL_PART_TABLES | 852K| 104 || 78 | VIEW | ALL_TAB_COMMENTS | 2043 | 14 || 93 | VIEW | ALL_EXTERNAL_LOCATIONS | 1744K| 31 || 106 | VIEW | ALL_EXTERNAL_TABLES | 1777K| 28 |------------------------------------------------------------------------------- That's much more like it. This drops the execution time down to 24 seconds. Not as good as 10g, but still an improvement. There are still several problems with this, however. 10g introduced a new join method - a right outer hash join (used in the first execution plan). The 9i query optimizer doesn't have this option available, so forcing a hash join means it has to hash the ALL_TABLES table, and furthermore re-hash it for every hash join in the execution plan; this could be thousands and thousands of rows. And although forcing hash joins somewhat alleviates this problem on our test systems, there's no guarantee that this will improve the execution time on customers' systems; it may even increase the time it takes (say, if all their tables are partitioned, or they've got a lot of materialized views). Ideally, we would want a solution that provides a speedup whatever the input. To try and get some ideas, we asked some oracle performance specialists to see if they had any ideas or tips. Their recommendation was to add a hidden hook into the product that allowed users to specify their own query hints, or even rewrite the queries entirely. However, we would prefer not to take that approach; as well as a lot of new infrastructure & a rewrite of the population code, it would have meant that any users of 9i would have to spend some time optimizing it to get it working on their system before they could use the product. Another approach was needed. All our population queries have a very specific pattern - a base table provides most of the information we need (ALL_TABLES for tables, or ALL_TAB_COLS for columns) and we do a left join to extra subsidiary tables that fill in gaps (for instance, ALL_PART_TABLES for partition information). All the left joins use the same set of columns to join on (typically the object owner & name), so we could re-use the hash information for each join, rather than re-hashing the same columns for every join. To allow us to do this, along with various other performance improvements that could be done for the specific query pattern we were using, we read all the tables individually and do a hash join on the client. Fortunately, this 'pure' algorithmic problem is the kind that can be very well optimized for expected real-world situations; as well as storing row data we're not using in the hash key on disk, we use very specific memory-efficient data structures to store all the information we need. This allows us to achieve a database population time that is as fast as on 10g, and even (in some situations) slightly faster, and a memory overhead of roughly 150 bytes per row of data in the result set (for schemas with 10,000 tables in that means an extra 1.4MB memory being used during population). Next: fun with the 9i dictionary views.

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  • IIS7 web farm - local or shared content?

    - by rbeier
    We're setting up an IIS7 web farm with two servers. Should each server have its own local copy of the content, or should they pull content directly from a UNC share? What are the pros and cons of each approach? We currently have a single live server WEB1, with content stored locally on a separate partition. A job periodically syncs WEB1 to a standby server WEB2, using robocopy for content and msdeploy for config. If WEB1 goes down, Nagios notifies us, and we manually run a script to move the IP addresses to WEB2's network interface. Both servers are actually VMs running on separate VMWare ESX 4 hosts. The servers are domain-joined. We have around 50-60 live sites on WEB1 - mostly ASP.NET, with a few that are just static HTML. Most are low-traffic "microsites". A few have moderate traffic, but none are massive. We'd like to change this so both WEB1 and WEB2 are actively serving content. This is mainly for reliability - if WEB1 goes down, we don't want to have to manually intervene to fail things over. Spreading the load is also nice, but the load is not high enough right now for us to need this. We're planning to configure our firewall to balance traffic across the two servers. It will detect when a server goes down and will send all the traffic to the remaining live server. We're planning to use sticky sessions for now... eventually we may move to SQL Server session state and stateless load balancing. But we need a way for the servers to share content. We were originally planning to move all the content to a UNC share. Our storage provider says they can set up a highly available SMB share for us. So if we go the UNC route, the storage shouldn't be a single point of failure. But we're wondering about the downsides to this approach: We'll need to change the physical paths for each site and virtual directory. There are also some projects that have absolute paths in their web.config files - we'll have to update those as well. We'll need to create a domain user for the web servers to access the share, and grant that user appropriate permissions. I haven't looked into this yet - I'm not sure if the application pool identity needs to be changed to this user, or if there's another way to tell IIS to use this account when connecting to the share. Sites will no longer be able to access their content if there's ever an Active Directory problem. In general, it just seems a lot more complicated, with more moving parts that could break. Our storage provider would create a volume for us on their redundant SAN. If I understand correctly, this SAN volume would be mounted on a VM running in their redundant VMWare environment; this VM would then expose the SMB share to our web servers. On the other hand, a benefit of the shared content approach is that we'd only need to deploy code to one place, and there would never be a temporary inconsistency between multiple copies of the content. This thread is pretty interesting, though some of these people are working at a much larger scale. I've just been discussing content so far, but we also need to think about configuration. I don't know if we can just use DFS replication for the applicationHost.config and other files, or if it's best to use the shared configuration feature with the config on a UNC share. What do you think? Thanks for your help, Richard

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  • Windows 7 Boot to VHD using a VHD clone of the system drive

    - by daveh551
    This seems like a not too difficult problem, and, after several hurdles, I'm maddeningly close. But I can't quite get there. I'm running Windows 7 in development shop. I want to start using VS2010 to work on some stuff that won't be released for awhile. My boss said no beta code on the production machine, but I could run VS2010 for this project IF I could do it in an isolated environment, like a virtual PC. Well, I've used the beta and RC of Win7 on VPC's before, and it was painfully slow because of the VPC environment. But everyone has been singing the praises of Windows 7's boot-to-VHD capability, where only the disk is virtualized, and you're actually running on the hardware. Supposed to be little slower, but nowhere near the speed penalty of VPC. I've spent a fair amount of time getting everything installed the way I want it. So I figured, I'll just clone my system drive using Disk2VHD, and boot off of that, and then install VS2010 onto that. (I keep most of my user data, including all my projects, in a separate partition, so that wouldn't have to be duplicated and would still be available.) Well, I had some difficulties with that, owing mainly to the fact that I was using an old version of Disk2VHD - (get the latest if you're going to try it.) But I did finally get it to boot. (Scott Hanselman has a good blog post on boot to VHD). But it wasn't exactly what I was expecting or hoping for. What I expected was that the VHD would become the C: drive, and the original (physical) C: drive would be either hidden or mounted under a different letter, and thus isolated and protected from any changes. What you actually get is that the VHD becomes the D: drive AND you boot from the D: drive, BUT your original C: drive is still there. Which is sort of okay EXCEPT that the Registry on the VHD is a clone of the Registry on C: drive, and includes many hard-coded references to C:. So the result is that some things come from (and modify) D: (the VHD), but some things come from (and modify) C:. (If you open a cmd prompt and do a SET to look at your environment variables, you will see a mixture of D:\ and C:\ paths.) So I don't really have an isolated environment. Most importantly, %ProgramFiles% is still set to C:\Program Files. What I really need is a tool that can access the registry files on the mounted VHD AS FILES, not as registry entries, and do a global search and replace on all the C:\ in strings to D:. I haven't found such a program. (I've tried to do it with a program called Registry Replace, but, even when running as Administrator, there are certain entries that the Registry won't let you change.) Does anyone know of one? Or any other solution to my problem (other than starting from scratch with a clean VHD and installing Win7 and all my programs on it.)?

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  • Splitting a raidctl mirror safely

    - by milkfilk
    I have a Sun T5220 server with the onboard LSI card and two disks that were in a RAID 1 mirror. The data is not important right now but we had a failed disk and are trying to understand how to do this for real if we had to recover from a failure. The initial situation looked like this: # raidctl -l c1t0d0 Volume Size Stripe Status Cache RAID Sub Size Level Disk ---------------------------------------------------------------- c1t0d0 136.6G N/A DEGRADED OFF RAID1 0.1.0 136.6G GOOD N/A 136.6G FAILED Green light on the 0.0.0 disk. Find / lights up the 0.1.0 disk. So I know I have a bad drive and which one it is. Server still boots obviously. First, we tried putting a new disk in. This disk came from an unknown source. Format would not see it, cfgadm -al would not see it so raidctl -l would not see it. I figure it's bad. We tried another disk from another spare server: # raidctl -c c1t1d0 c1t0d0 (where t1 is my good disk - 0.1.0) Disk has occupied space. Also the different syntax options don't change anything: # raidctl -C "0.1.0 0.0.0" -r 1 1 Disk has occupied space. # raidctl -C "0.1.0 0.0.0" 1 Disk has occupied space. Ok. Maybe this is because the disk from the spare server had a RAID 1 on it already. Aha, I can see another volume in raidctl: # raidctl -l Controller: 1 Volume:c1t1d0 (this is my server's root mirror) Volume:c1t132d0 (this is the foreign root mirror) Disk: 0.0.0 Disk: 0.1.0 ... No problem. I don't care about the data, I'll just delete the foreign mirror. # raidctl -d c1t132d0 (warning about data deletion but it works) At this point, /usr/bin/ binaries freak out. By that I mean, ls -l /usr/bin/which shows 1.4k but cat /usr/bin/which gives me a newline. Great, I just blew away the binaries (ie: binaries in mem still work)? I bounce the box. It all comes back fine. WTF. Anyway, back to recreating my mirror. # raidctl -l Controller: 1 Volume:c1t1d0 (this is my server's root mirror) Disk: 0.0.0 Disk: 0.1.0 ... Man says that you can delete a mirror and it will split it. Ok, I'll delete the root mirror. # raidctl -d c1t0d0 Array in use. (this might not be the exact error) I googled this and found of course you can't do this (even with -f) while booted off the mirror. Ok. I boot cdrom -s and deleted the volume. Now I have one disk that has a type of "LSI-Logical-Volume" on c1t1d0 (where my data is) and a brand new "Hitachi 146GB" on c1t0d0 (what I'm trying to mirror to): (booted off the CD) # raidctl -c c1t1d0 c1t0d0 (man says it's source destination for mirroring) Illegal Array Layout. # raidctl -C "0.1.0 0.0.0" -r 1 1 (alt syntax per man) Illegal Array Layout. # raidctl -C "0.1.0 0.0.0" 1 (assumes raid1, no help) Illegal Array Layout. Same size disks, same manufacturer but I did delete the volume instead of throwing in a blank disk and waiting for it to resync. Maybe this was a critical error. I tried selecting the type in format for my good disk to be a plain 146gb disk but it resets the partition table which I'm pretty sure would wipe the data (bad if this was production). Am I boned? Anyone have experience with breaking and resyncing a mirror? There's nothing on Google about "Illegal Array Layout" so here's my contrib to the search gods.

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  • Determining cause of high NFS/IO utilization without iotop

    - by Matt
    I have a server that is doing an NFSv4 export for user's home directories. There are roughly 25 users (mostly developers/analysts) and about 40 servers mounting the home directory export. Performance is miserable, with users often seeing multi-second lags for simple commands (like ls, or writing a small text file). Sometimes the home directory mount completely hangs for minutes, with users getting "permission denied" errors. The hardware is a Dell R510 with dual E5620 CPUs and 8 GB RAM. There are eight 15k 2.5” 600 GB drives (Seagate ST3600057SS) configured in hardware RAID-6 with a single hot spare. RAID controller is a Dell PERC H700 w/512MB cache (Linux sees this as a LSI MegaSAS 9260). OS is CentOS 5.6, home directory partition is ext3, with options “rw,data=journal,usrquota”. I have the HW RAID configured to present two virtual disks to the OS: /dev/sda for the OS (boot, root and swap partitions), and /dev/sdb for the home directories. What I find curious, and suspicious, is that the sda device often has very high utilization, even though it only contains the OS. I would expect this virtual drive to be idle almost all the time. The system is not swapping, according to "free" and "vmstat". Why would there be major load on this device? Here is a 30-second snapshot from iostat: Time: 09:37:28 AM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sdb 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 sdb1 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 dm-0 0.00 0.00 0.03 151.82 0.13 607.26 8.00 1.25 8.23 5.16 78.35 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 dm-3 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 Looks like iotop is the ideal tool to use to sniff out these kinds of issues. But I'm on CentOS 5.6, which doesn't have a new enough kernel to support that program. I looked at Determining which process is causing heavy disk I/O?, and besides iotop, one of the suggestions said to do a "echo 1 /proc/sys/vm/block_dump". I did that (after directing kernel messages to tempfs). In about 13 minutes I had about 700k reads or writes, roughly half from kjournald and the other half from nfsd: # egrep " kernel: .*(READ|WRITE)" messages | wc -l 768439 # egrep " kernel: kjournald.*(READ|WRITE)" messages | wc -l 403615 # egrep " kernel: nfsd.*(READ|WRITE)" messages | wc -l 314028 For what it's worth, for the last hour, utilization has constantly been over 90% for the home directory drive. My 30-second iostat keeps showing output like this: Time: 09:36:30 PM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sdb 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 sdb1 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 dm-0 0.00 0.00 0.20 17.76 0.80 71.04 8.00 0.38 21.21 9.22 16.57 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.81 dm-3 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.82

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  • Windows 7 .NET 3.5.1 - 2.0 Slightly Corrupted, How to Repair?

    - by Quinxy von Besiex
    My Windows 7 included .NET installation (3.5 to 2.0) appears very slightly and particularly corrupted and I am trying to fix it without reinstalling Windows or trying to revert to backups. Everything was working and then my hard drive started corrupting a few files and checkdisk found bad clusters so I imaged the drive to a new one. As soon as I booted on the new drive everything worked except programs which call the System.Net.NetworkInformation methods within .NET 3.5 to 2.0 (like Ping() and IsNetworkAvailable()), which immediately crash the app in which the calls are (those calls in .NET 4.0 works fine). Those methods are found inside System.dll, and I assume call native methods which I believe are inside winnsi.dll or iphlpapi.dll or something else (I've not found this yet); I assume it calls native methods because the exception which causes the crash is Fatal Execution Engine Error which people mention is usually related to calling native methods and marshaling data between them. A huge clue about the culprit is likely found in the fact that when I launch the exact same crashing application through a code profiler (which executes the exe and captures stats on which methods took the longest) the app works fine, no crash at all! How could running it within the profiler work and running it outside not work? That seems the key to the mystery. I've used procmon to catch all the registry, filesystem, and network events from the crashing execution and the profiler-run successful execution and compared the two outputs but didn't learn much (I see the moment at which the non-profiled app crashes, but up until then they behave the same, loaded the same modules, ). The only big difference seems to be that at the moment before the app crash the profiler-executed code creates 4-6 new threads and the directly executed code only creates 1-2. I have diffed the files/directories which seemed most relevant (the .NET stuff under Windows and Program Files) pre- and post- disk trouble and seen no changes where I didn't expect any (no obvious file corruption). I have diffed the software and system registry hives pre- and post- disk trouble and seen no changes which seemed relevant. I have created a new user account and cleaned up any environment variables in case environment was related. No change. I did "sfc /scannow" and it found no integrity problems. I tried "ngen update" to regenerate pre-compiled code in case I missed something that might be damaged and nothing changed. I assume I need to repair my .NET installation but because Windows 7 included .NET 3.5 - 2.0 you can't just re-run a .NET installer to redo it. I do not have access to the Windows disks to try to re-install Windows over itself (the computer has a recovery partition but it is unusable); also the drive uses a whole-disk encryption solution and re-installing would be difficult. I absolutely do not want to start from scratch here and install a fresh Windows, reinstall dozens of software packages, try and remember dozens of development-related customizations/etc. Given all that... does anyone have any helpful advice? I need .NET 3.5 - 2.0 working as I am a developer and need to build and test against it. Thanks! Quinxy

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  • How to get rid of a stubborn 'removed' device in mdadm

    - by T.J. Crowder
    One of my server's drives failed and so I removed the failed drive from all three relevant arrays, had the drive swapped out, and then added the new drive to the arrays. Two of the arrays worked perfectly. The third added the drive back as a spare, and there's an odd "removed" entry in the mdadm details. I tried both mdadm /dev/md2 --remove failed and mdadm /dev/md2 --remove detached as suggested here and here, neither of which complained, but neither of which had any effect, either. Does anyone know how I can get rid of that entry and get the drive added back properly? (Ideally without resyncing a third time, I've already had to do it twice and it takes hours. But if that's what it takes, that's what it takes.) The new drive is /dev/sda, the relevant partition is /dev/sda3. Here's the detail on the array: # mdadm --detail /dev/md2 /dev/md2: Version : 0.90 Creation Time : Wed Oct 26 12:27:49 2011 Raid Level : raid1 Array Size : 729952192 (696.14 GiB 747.47 GB) Used Dev Size : 729952192 (696.14 GiB 747.47 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Persistence : Superblock is persistent Update Time : Tue Nov 12 17:48:53 2013 State : clean, degraded Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 UUID : 2fdbf68c:d572d905:776c2c25:004bd7b2 (local to host blah) Events : 0.34665 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 19 1 active sync /dev/sdb3 2 8 3 - spare /dev/sda3 If it's relevant, it's a 64-bit server. It normally runs Ubuntu, but right now I'm in the data centre's "rescue" OS, which is Debian 7 (wheezy). The "removed" entry was there the last time I was in Ubuntu (it won't, currently, boot from the disk), so I don't think that's not some Ubuntu/Debian conflict (and they are, of course, closely related). Update: Having done extensive tests with test devices on a local machine, I'm just plain getting anomalous behavior from mdadm with this array. For instance, with /dev/sda3 removed from the array again, I did this: mdadm /dev/md2 --grow --force --raid-devices=1 And that got rid of the "removed" device, leaving me just with /dev/sdb3. Then I nuked /dev/sda3 (wrote a file system to it, so it didn't have the raid fs anymore), then: mdadm /dev/md2 --grow --raid-devices=2 ...which gave me an array with /dev/sdb3 in slot 0 and "removed" in slot 1 as you'd expect. Then mdadm /dev/md2 --add /dev/sda3 ...added it — as a spare again. (Another 3.5 hours down the drain.) So with the rebuilt spare in the array, given that mdadm's man page says RAID-DEVICES CHANGES ... When the number of devices is increased, any hot spares that are present will be activated immediately. ...I grew the array to three devices, to try to activate the "spare": mdadm /dev/md2 --grow --raid-devices=3 What did I get? Two "removed" devices, and the spare. And yet when I do this with a test array, I don't get this behavior. So I nuked /dev/sda3 again, used it to create a brand-new array, and am copying the data from the old array to the new one: rsync -r -t -v --exclude 'lost+found' --progress /mnt/oldarray/* /mnt/newarray This will, of course, take hours. Hopefully when I'm done, I can stop the old array entirely, nuke /dev/sdb3, and add it to the new array. Hopefully, it won't get added as a spare!

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  • MySQL 5.5 (Percona) assertion failure log.. what would cause this?

    - by Tom Geee
    256GB, 64 Core , AMD running Ubuntu 12.04 with Percona MySQL 5.5.28. Below is the assertion failure. We just had a second assertion failure (different "in file", position, etc) while running a large set of inserts. After the first failure, MySQL restarted after a reboot only - after continuously looping on the same error after trying to recover. I decided to do a mysqlcheck with -o for optimize. Since these are all Innodb tables (very large tables, 60+GB) this would do an alter table on all tables. In the middle of this , the below assertion failure happened again: 121115 22:30:31 InnoDB: Assertion failure in thread 140086589445888 in file btr0pcur.c line 452 InnoDB: Failing assertion: btr_page_get_prev(next_page, mtr) == buf_block_get_page_no(btr_pcur_get_block(cursor)) InnoDB: We intentionally generate a memory trap. InnoDB: Submit a detailed bug report to http://bugs.mysql.com. InnoDB: If you get repeated assertion failures or crashes, even InnoDB: immediately after the mysqld startup, there may be InnoDB: corruption in the InnoDB tablespace. Please refer to InnoDB: http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html InnoDB: about forcing recovery. 03:30:31 UTC - mysqld got signal 6 ; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. Please help us make Percona Server better by reporting any bugs at http://bugs.percona.com/ key_buffer_size=536870912 read_buffer_size=131072 max_used_connections=404 max_threads=500 thread_count=90 connection_count=90 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 1618416 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x14edeb710 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 7f687366ce80 thread_stack 0x30000 /usr/sbin/mysqld(my_print_stacktrace+0x2e)[0x7b52ee] /usr/sbin/mysqld(handle_fatal_signal+0x484)[0x68f024] /lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0)[0x7f9cbb23fcb0] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x35)[0x7f9cbaea6425] /lib/x86_64-linux-gnu/libc.so.6(abort+0x17b)[0x7f9cbaea9b8b] /usr/sbin/mysqld[0x858463] /usr/sbin/mysqld[0x804513] /usr/sbin/mysqld[0x808432] /usr/sbin/mysqld[0x7db8bf] /usr/sbin/mysqld(_Z13rr_sequentialP11READ_RECORD+0x1d)[0x755aed] /usr/sbin/mysqld(_Z17mysql_alter_tableP3THDPcS1_P24st_ha_create_informationP10TABLE_LISTP10Alter_infojP8st_orderb+0x216b)[0x60399b] /usr/sbin/mysqld(_Z20mysql_recreate_tableP3THDP10TABLE_LIST+0x166)[0x604bd6] /usr/sbin/mysqld[0x647da1] /usr/sbin/mysqld(_ZN24Optimize_table_statement7executeEP3THD+0xde)[0x64891e] /usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0x1168)[0x59b558] /usr/sbin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x30c)[0x5a132c] /usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1620)[0x5a2a00] /usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0x14f)[0x63ce6f] /usr/sbin/mysqld(handle_one_connection+0x51)[0x63cf31] /lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a)[0x7f9cbb237e9a] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f9cbaf63cbd] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (7f6300004b60): is an invalid pointer Connection ID (thread ID): 876 Status: NOT_KILLED You may download the Percona Server operations manual by visiting http://www.percona.com/software/percona-server/. You may find information in the manual which will help you identify the cause of the crash. 121115 22:31:07 [Note] Plugin 'FEDERATED' is disabled. 121115 22:31:07 InnoDB: The InnoDB memory heap is disabled 121115 22:31:07 InnoDB: Mutexes and rw_locks use GCC atomic builtins .. Then it recovered , without a reboot this time. from the log, what would cause this? I am currently running a dump to see if the problem resurfaces. edit: data partition is all in / since this is a hosted, defaulted file system unfortunately: Filesystem Size Used Avail Use% Mounted on /dev/vda3 742G 445G 260G 64% / udev 121G 4.0K 121G 1% /dev tmpfs 49G 248K 49G 1% /run none 5.0M 0 5.0M 0% /run/lock none 121G 0 121G 0% /run/shm /dev/vda1 99M 54M 40M 58% /boot my.cnf: [client] port = 3306 socket = /var/run/mysqld/mysqld.sock [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] skip-name-resolve innodb_file_per_table default_storage_engine=InnoDB user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /data/mysql tmpdir = /tmp skip-external-locking key_buffer = 512M max_allowed_packet = 128M thread_stack = 192K thread_cache_size = 64 myisam-recover = BACKUP max_connections = 500 table_cache = 812 table_definition_cache = 812 #query_cache_limit = 4M #query_cache_size = 512M join_buffer_size = 512K innodb_additional_mem_pool_size = 20M innodb_buffer_pool_size = 196G #innodb_file_io_threads = 4 #innodb_thread_concurrency = 12 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 8M innodb_log_file_size = 1024M innodb_log_files_in_group = 2 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 log_error = /var/log/mysql/error.log long_query_time = 5 slow_query_log = 1 slow_query_log_file = /var/log/mysql/slowlog.log [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] [isamchk] key_buffer = 16M

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  • apache webserver unresponsible with server-status showing all child processes waiting for connection

    - by Jeff
    My setup: i have 3 nearly identical webserver machines serving the same high loaded dynamic website with simple load balancing over dns. The service has been working for over two ears with the same apache config. apache2, php5, ubuntu 8.04 linux 2.6.24-29-server My problem: since about two weeks i'm experiencing problems with this config. Nearly every day i have one small moment about 5 minutes, in which the website is unreachable. I'm still able to login to the servers over ssh. If i run htop, i see the machine simply doing nothing. i have about 1000 apache processes running, but no cpu activity. i've used the apache mod_status to debug this situation. the process scoreboard looks like this: _C.___K_______________________R._______.__K_K____K___C_______.__ _______C__________.___________________________________.________C _.____K__________K___K_WK_____._K_____________________________._ W______K__________K________.____________________._______C_______ _C_.__K__K____.._.._____________________________________C_______ _R___________K___.______C________.C_________.______._____C______ ____________KKC____K_____K__WC_________________C_____.__.____.__ _____________________C_________K______.____C______._____________ _.___C____.___.___________________________.K______.____K________ W__.___________________C.__.____K________K_______R_._.__._______ __C__C_.__________C__C_______._____W______________C_.___C_______ ____.______C_____________C________.____C____________.________._K __.__________.K_____________K_________._____C____.K__________KW_ __K.W________R_________._______.___W___________.____.__K_____W__ W___.___..________W____K Scoreboard Key: "_" Waiting for Connection, "S" Starting up, "R" Reading Request, "W" Sending Reply, "K" Keepalive (read), "D" DNS Lookup, "C" Closing connection, "L" Logging, "G" Gracefully finishing, "I" Idle cleanup of worker, "." Open slot with no current process So the most of the processes are just waiting for connection. after about 5 minutes the situation will return to normal: i have lot least processes on every machine, the most workers have the "."-status (meaing they are open to process a request) and of course the website is reachable! so i'm trying to find something in the logs, but there is simply nothing... the apache access log is silent for about 4 minutes, the same is for the error log. i also can not figure out anything wrong in other system logs. the situation is the same on all 3 webservers (all of them have this load peak and unresposibility at the same time), so i do not thing this is hardware related. but i think, this might be related to some network (tcp) issue. any ideas? EDIT: some more information, that i have just discovered: it has just happened again. and i was able to verify that i'm also not able to connect locally when this problem occurs. i have made some connection statistics with the following command after it happend netstat -an|awk '/tcp/ {print $6}'|sort|uniq -c 109 CLOSE_WAIT 2652 ESTABLISHED 2 FIN_WAIT1 11 LAST_ACK 12 LISTEN 91 SYN_RECV 1 SYN_SENT 16 TIME_WAIT If i execute the same command some time later, i have something like this: 4 CLOSING 108 ESTABLISHED 18 FIN_WAIT1 182 FIN_WAIT2 37 LAST_ACK 12 LISTEN 50 SYN_RECV 11276 TIME_WAIT So in the normal situation i have only 100-200 open connections by clients beeing handled by apache in this moment. when i have this "crash", i have a lot more connections. what is the best way to analyse this? EDIT2: the important lines in apache2.conf are: KeepAlive On MaxKeepAliveRequests 20 KeepAliveTimeout 1 <IfModule mpm_prefork_module> ServerLimit 920 StartServers 30 MinSpareServers 80 MaxSpareServers 120 MaxClients 920 MaxRequestsPerChild 700 </IfModule> it is an apache2 prefork with php_mod. the server has 8GB ram and a 4gb swap partition.

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  • Causes of sudden massive filesystem damage? ("root inode is not a directory")

    - by poolie
    I have a laptop running Maverick (very happily until yesterday), with a Patriot Torx SSD; LUKS encryption of the whole partition; one lvm physical volume on top of that; then home and root in ext4 logical volumes on top of that. When I tried to boot it yesterday, it complained that it couldn't mount the root filesystem. Running fsck, basically every inode seems to be wrong. Both home and root filesystems show similar problems. Checking a backup superblock doesn't help. e2fsck 1.41.12 (17-May-2010) lithe_root was not cleanly unmounted, check forced. Resize inode not valid. Recreate? no Pass 1: Checking inodes, blocks, and sizes Root inode is not a directory. Clear? no Root inode has dtime set (probably due to old mke2fs). Fix? no Inode 2 is in use, but has dtime set. Fix? no Inode 2 has a extra size (4730) which is invalid Fix? no Inode 2 has compression flag set on filesystem without compression support. Clear? no Inode 2 has INDEX_FL flag set but is not a directory. Clear HTree index? no HTREE directory inode 2 has an invalid root node. Clear HTree index? no Inode 2, i_size is 9581392125871137995, should be 0. Fix? no Inode 2, i_blocks is 40456527802719, should be 0. Fix? no Reserved inode 3 (<The ACL index inode>) has invalid mode. Clear? no Inode 3 has compression flag set on filesystem without compression support. Clear? no Inode 3 has INDEX_FL flag set but is not a directory. Clear HTree index? no .... Running strings across the filesystems, I can see there are what look like filenames and user data there. I do have sufficiently good backups (touch wood) that it's not worth grovelling around to pull back individual files, though I might save an image of the unencrypted disk before I rebuild, just in case. smartctl doesn't show any errors, neither does the kernel log. Running a write-mode badblocks across the swap lv doesn't find problems either. So the disk may be failing, but not in an obvious way. At this point I'm basically, as they say, fscked? Back to reinstalling, perhaps running badblocks over the disk, then restoring from backup? There doesn't even seem to be enough data to file a meaningful bug... I don't recall that this machine crashed last time I used it. At this point I suspect a bug or memory corruption caused it to write garbage across the disks when it was last running, or some kind of subtle failure mode for the SSD. What do you think would have caused this? Is there anything else you'd try?

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  • How to delete files and folders that cannot be deleted?

    - by glenneroo
    I have a backup copy of a previous Windows' Documents and Settings folder which only contains my original user and within 2 more directories: Favorites and Local Settings. When I try to delete Local Settings I get this error: When I try to delete Favorites, I get this error: I ran this in a cmd shell: attrib *.* -r -a -s -h /s ...but it did not help, nor did it return any errors/warnings. I used Unlocker v1.8.5 and LockHunter repeatedly at multiple levels to see if any files are in use, but both always say: No Files Locked. Update #1: I was able to rename the directory, which now gives me this warning before (trying to) delete: If I press Yes (or Yes to All) then I get this error: Update #2: I let chkdsk /f run which required a reboot since it's on my primary system partition. During Stage 2 scanning, I received about 40 of these: Deleting an index entry from index $0 of file 25. ...followed by: Deleting index entry cookies in index $I30 of file 37576. ...but I still get the first error dialog above when trying to delete. I ran chkdsk again, this time: chkdsk /f /r. Produced no messages. Same result when deleting. Update #3: Digging deeper, the 99 is the name of one of many directories located deep in here: C:\Documents and Settings.OLD\User\Local Settings\Application Data\Microsoft\Messenger\[email protected]\SharingMetadata\[email protected]\DFSR\Staging\CS{D4E4AE55-B5E2-F03B-5189-6C4DA6E41788}\ Inside each of those directories were files with names such as: 2300-{C93D01AC-0739-4FD9-88C7-13D2F21A208E}-v2300-{C93D01AC-0739-4FD9-88C7-13D2F21A208E}-v2300-Downloaded.frx I noticed that, unlike all the directories, I couldn't rename any of these files. I also noticed that the file + dir names were extremely long: Original directory = 194 characters Filenames = 100+ characters Together the length exceeds the 255-char limit which is bad and would explain the error message I posted in Update #1. Partial Solution: Rename all directories until the total path length is less than 100. Afterwards I was able to rename the .frx files, not to mention delete everything inside the Local Settings directory. This is only a partial solution because these (empty) directories are still not deleteable, C:\1\2\Favorites\Wien\What To Do.. C:\1\2\Favorites\Photography\FIRE Same error as above: Here is what Explorer properties shows for both folders: Update #4 (another partial solution): Using harrymc's answer combined with thoroughly reading through this amazing MS-KB article which contains nearly everyone's idea and then some, inconspicuously titled: You cannot delete a file or a folder on an NTFS file system volume. I was able to delete the 2nd folder C:\1\2\Favorites\Photography\FIRE - the problem being that there was an invisible trailing space at the end. I got lucky when I did an auto-complete whilst playing around with the del "\\?\<path>" command which he suggested. NOTE: A normal del did NOT work, nor did deleting from explorer. Now all that is left is the first directory C:\1\2\Favorites\Wien\What To Do.. (yes I tried endlessly with multiple combinations of the above solution ;) Keep 'em coming! =)

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  • How to use more than 3 virtual disks in Linux using CentOS and XenServer

    - by 010110110101
    I've attached 5 virtual disks to a Virtual Machine in Citrix XenServer. The VM has the xs-tools installed. Initially it said that it couldn't add so many disks. After I installed the xs-tools, it let me add all the disks. But /dev doesn't show all the disks. It shows these: /dev/xvda /dev/xvdb /dev/xvdc /dev/cdrom Perhaps it is bound by the limits of an IDE bus? (3 disks + CD-ROM) If so, how does one change the VM to use SCSI? Edit: According to the documentation: 2.6.3. VM Block Devices In the PV Linux case, block devices are passed through as PV devices. XenServer does not attempt to emulate SCSI or IDE, but instead provides a more suitable interface in the virtual environment in the form of xvd* devices. It is also possible to get an sd* device using the same mechanism, where the PV driver inside the VM takes over the SCSI device namespace. This is not desirable so it is best to use xvd* where possible for PV guests (this is the default for Debian and RHEL). For Windows or other fully virtualized guests, XenServer emulates an IDE bus in the form of an hd* device. When using Windows, installing the Citrix Tools for Virtual Machines installs a special PV driver that works in a similar way to Linux, except in the fully virtualized environment. Still, with 5 virtual disks attached, I don't see the other xvd devices. Edit #2: (attached requested info) Host Machine: XenServer 6.1 Linux version 2.6.32.43-0.4.1.xs1.6.10.777.170770xen (geeko@buildhost) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-51)) #1 SMP Wed Apr 17 05:52:03 EDT 2013 Guest Machine: CentOS release 6.4 (Final) Linux version 2.6.32-358.6.2.el6.x86_64 ([email protected]) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) ) #1 SMP Thu May 16 20:59:36 UTC 2013 Output of 'fdisk -l' on Guest Machine: Note, the disk beyond the first 3 attached are not displaying -- there should be 4 100GB disks. (There are a total of 5 disks displayed in XenCenter -- 16GB, 100GB, 100GB, 100GB, 100GB) Disk /dev/xvdb: 107.4 GB, 107374182400 bytes 255 heads, 63 sectors/track, 13054 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xfb6c95b9 Device Boot Start End Blocks Id System /dev/xvdb1 1 13054 104856223+ 83 Linux Disk /dev/xvda: 17.2 GB, 17179869184 bytes 255 heads, 63 sectors/track, 2088 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000e5f41 Device Boot Start End Blocks Id System /dev/xvda1 * 1 64 512000 83 Linux Partition 1 does not end on cylinder boundary. /dev/xvda2 64 2089 16264192 8e Linux LVM Disk /dev/xvdc: 107.4 GB, 107374182400 bytes 255 heads, 63 sectors/track, 13054 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xed249ced Device Boot Start End Blocks Id System /dev/xvdc1 1 13054 104856223+ 83 Linux Disk /dev/mapper/vg_blue-lv_root: 14.6 GB, 14571012096 bytes 255 heads, 63 sectors/track, 1771 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/mapper/vg_blue-lv_swap: 2080 MB, 2080374784 bytes 255 heads, 63 sectors/track, 252 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 I see that the Linux versions say SMP. The Guest VM doesn't say "xen" in the name. However, I have already run yum install kernel-xen. Could be a clue?

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  • File copying utility like rsync with error handling like ddrescue, for data recovery from a hard drive with bad sectors or hardware failure

    - by purefusion
    I have a hard drive with either bad blocks or sectors that are failing to read due to potential mechanical issues, such as a bad disk head, bad motor, or some other issue that is causing the hard drive to read data excruciatingly slowly and with lots of read errors. I'm seeing an average of 50 KB/sec, with some reads dropping below 10 KB/sec, and frequently it gets stuck on a file or sector altogether, usually for quite a long time—from 2-10 minutes or more (when using rsync, before it times out). Speed seems to vary wildly, and it gets stuck on files a lot, and when it finally gets "unstuck" it only seems to last for a short burst before it gets stuck again. The drive is also very quiet with only an occasional sound of files copying (usually when it gets stuck/unstuck for a brief time, before getting stuck again). Thus, there are none of those evil sounds that are normally associated with HDD death. Someone suggested that the problems sounded like they might be caused by a misaligned disk head, which requires a lot of re-reads before it finally reads data with success. Sounds plausible, but I digress... Anyway, the problem with rsync is that it seems to have no decent error handling support. Obviously, it wasn't meant for use in recovering data from failing hard drives, but all the so-called "data recovery" utilities out there that are meant for such use usually focus on recovery of deleted files or messed up partitions, rather than copying files off dying hard drives. Deleted file recovery is not what I need, obviously, so perhaps you can understand my disappointment in not being able to find what I'm after yet. Naturally, this is where you'd probably say "You should use ddrescue!" Well, that's all fine and dandy, but I've already got most of the data backed up, so I just want to recover certain files. I'm not concerned with trying to recover a full partition block-by-block as ddrescue does. I am only interested in rescuing just specific files and directories. Ideally, what I'd like is some sort of cross between rsync and ddrescue: something that lets me specify source and destination as directories of normal files like rsync (rather than two full partitions as ddrescue requires), with a way to skip files with errors in an initial run, and then allows me to attempt recovery of those files with errors in a later run (with a slightly altered command, of course), perhaps even offering an option to specify the number of retry attempts ...just like how ddrescue works with blocks, only I want a utility that works with specific files/directories like rsync does. So am I daydreaming here, or does something out there exist that can do this? Or, maybe even a way to make rsync or ddrescue work in such a way? I'm really open to whatever solutions might work, so long as they let me choose which files I want to "rescue", and can skip files with errors in the initial run, and try/retry those errors again later. So far I've tried rsync with the following options, but it often gets stuck on a file for longer than the timeout, and ideally I'd just like it to move on to the next file and come back later to the files it gets stuck on. I don't think that's possible though. Anyway, here's what I've been using up till now: rsync -avP --stats --block-size=512 --timeout=600 /path/to/source/* /path/to/destination/

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  • Using different SSDs types (not only SATA based) as system drive

    - by Hubert Kario
    Currently I have a Thinkpad X61s and want to make it both a bit faster and a bit more power efficient. For that reason I thought that adding SSD drive would make most sense. Unfortunately, because of financial reasons, buying SSD of over 200GB capacity is out of reach for me (not only it would be worth more than the rest of the laptop, but also I currently have a 500GB drive in it, so even such a drive would be kind of a downgrade for me). During preliminary testing with a cheap Transcend 4GB Class 6 (14MiB/s streaming, 9MiB/s random read) card I experienced boot times to be reduced by half so putting the OS only on it would already would be an improvement. Unfortunately, my system now is about 11GiB in size so anything less than 16GB would be constraining. In this laptop I can connect additional drives on at least 5 different ways: using SATA-ATA converter caddy in the X6 Ultrabase using internal mini PCIe slot using integrated SDHC slot using CardBus (a.k.a PCMCIA or PC Card) slot using USB Thankfully, because I use only Linux on this PC the bootability of them is irrelevant as I can put the /boot partition on internal HDD and / on any of the above mentioned Flash memories (as I already did for the SDHC test). From what I was able to research and from my own experience those options come with rather big downsides or other problems: SATA-ATA caddy It has three downsides: I have to carry the Ultrabse with me at all times (it's not really inconvenient, but those grams do add) and couldn't disconnect it when I want to disconnect the battery It makes the bay unusable for the optical drive and occasional quick access to other hard drives the only caddies I could buy have rather flaky controllers in them so putting my OS on it would hamper its stability Internal mini PCIe slot This would be an ideal solution, if only I could find real PCIe SSDs, not only devices that could talk only SATA or ATA over PCIe mechanical connection (the ones used in Dell Mini or Asus EEE). Theoretically Samsung did release such devices but I couldn't find them in retail anywhere. Integrated SDHC slot It's a nice solution with a single drawback: the fastest 16GB SDHC card on the market can only do around 35MiB/s read and 15MiB/s write while still costing like a normal 40GB SATA SSD that's 10 times faster. Not really cost-effective. CardBus (a.k.a PCMCIA or PC Card) slot Those cards are much faster than the SDHC option (there are ones that can do well over 50MiB/s read in benchmarks) and from what I could find the PCMCIA controller in my laptop does support UDMA so it should be able to deliver comparable speeds. They still cost similarly to SD cards but at least they provide streaming performance comparable to my current HDD. USB That's the worst option. Not only is it limited to 20-30MiB/s by the interface itself the drive would stick out of the laptop so it's a big no no. The question As such I think that going the "CF in a CardBus adapter" route will be the best option. My question is: did anyone try using CF cards in CardBus adapters as system drives with Linux on Thinkpad laptops? Laptops in general? What was the real-world performance? I don't have any CF cards so I can't check how well does it work with suspend/resume, or whatever it's easy to make it work in initramfs (I'm using ArchLinux and SD card was trivial — add 3 modules in single config line and rebuilding initramfs) so any tips/gotchas on this are welcome as well.

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  • Do hard drive enclosures fail/is it the HDD or enclosure?

    - by x0a
    I'm having a whole host of problems with an external hard drive that was working just fine a couple of hours ago. I've had this problem before once, and that was about 3 months ago, here's what I documented: So a couple of hours ago I turned off all my computers and shut off the power to all my devices in my room, then went and turned the power off at the main switch so I could change an outlet. A couple hours later, after I've already slowly turned everything back on, I go to my xbox to try and watch a movie and it can't seem to list any of the movies I've got. So I go to my desktop to find that my external hard drive isn't there.. even though it's on and connected. It's also stationary and hidden behind something so there's not a whole lot of tampering/physical wear to that external. I plug it into my laptop to try and see what's going on. It starts making this endless loud screeching noise. None of that clicking that's usually associated with hd damage. It's not listed in my computers, and it shows up in Disk Management as "uninitialized" asking me to choose between two different partition types. After carefully disconnecting it and connecting it back, it asks me to format it, which I cancel. I start googling about my issue, starting to accept the situation, torn as hell and helpless and just about ready to toss the thing. Suddenly the screeching stops, after almost 45 minutes of it going, and Disk Management lists the drive as "Online" and "Healthy". Explorer pops up with all my files! I'm still being really careful with it and weary and treating it as though it's in fragile shape. I've downloaded some S.M.A.R.T. software to read the values and everything is listed as "OK" . No reallocated sectors, no read errors, no seek errors. I also ran a quick self-test, which completed without error. Everything seems fine. It looks to be a perfectly healthy external hard drive. So what the hell was that about? Was it doing some sort of maintenance or self-test? How am I supposed to tell the difference? I would've undoubtedly killed the drive for sure if had it gone on a bit longer. I've got the same problem now, with one exception: it doesn't magically reappear after the screeching stops. Occasionally I manage to get some S.M.A.R.T. diagnostics information, which basically reads everything as fine. The only problem is that my HD isn't initializing (so I can't access anything in it). I'm able to successfully run a quick smart test but not an extended one (I've only tried it once but got conflicting indications as to whether it was actually making any progress or not (was stuck on Random read test). So, final question (if all else fails): Could the hard drive enclosure be failing rather than the HDD? Is this a likely possibility at all? How would I know?

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  • How can I recover an ext4 filesystem corrupted after a fsck?

    - by Regan
    I have an ext4 filesystem on luks over software raid5. The filesystem was operating "just fine" for several years when I was beginning to run out of space. I had a 9T volume on 6x2T drives. I began upgrading to 3T drives by doing the mdadm fail, remove, add, rebuild, repeat process until I had a larger array. I then grew the luks container, and then when I unmounted and tried to resize2fs I was given the message the filesystem was dirty and needed e2fsck. Without thinking I just did e2fsck -y /dev/mapper/candybox and it began spewing all kinds of inode being removed type messages (can't remember exactly) I killed e2fsck and tried to remount the filesystem to backup data I was concerned about. When trying to mount at this point I get: # mount /dev/mapper/candybox /candybox mount: wrong fs type, bad option, bad superblock on /dev/mapper/candybox, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so Looking back at my older logs I noticed the filesystem was giving this error each time the machine booted: kernel: [79137.275531] EXT4-fs (dm-2): warning: mounting fs with errors, running e2fsck is recommended So shame on me for not paying attention :( I then tried to mount using every backup superblock (one after another) and each attempt left this in my log: EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 0 failed (26534!=65440) EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 1 failed (38021!=36729) EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 2 failed (18336!=39845) ... EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 11911 failed (28743!=44098) BUG: soft lockup - CPU#0 stuck for 23s! [mount:2939] Attempts to restart e2fsck results in: # e2fsck /dev/mapper/candybox e2fsck 1.41.14 (22-Dec-2010) e2fsck: Group descriptors look bad... trying backup blocks... candy: recovering journal e2fsck: unable to set superblock flags on candy At this point, I decided it best to order some more drives and make an image using ddrescue Now two weeks later I have an image of the luks partition in a .img file. # ls -lh total 14T -rw-r--r-- 1 root root 14T Oct 25 01:57 candybox.img -rw-r--r-- 1 root root 271 Oct 20 14:32 candybox.logfile After numerous attempts using everything I could find online I could not coerce e2fsck to do anything on the image, so I used mkfs.ext4 -L candy candybox.img -m 0 -S and I was able to mount the dirty filesystem readonly without the journal and recover 960G of data. It gave all kinds of errors of various directories not existing and so forth but I was able to get some stuff. Which gave me some hope! I then ran e2fsck again and it had to recreate the root inode and gave a massive list of correcting group counts, I accepted the root inode creation and said no to everything else, leaving a completely empty filesystem. Re-ran again and said yes to all questions with the same result but now a "clean" but empty filesystem. extundelete gives me 0 recoverable inodes found. And now I'm stuck again, I can't come up with any other methods other than dropping to something like photorec which will give me an absolute mess with how large the filesystem was. I'm willing to re-copy the image from the original array and start over, if I can get any suggestions or ideas on a way to get more of my files back. I wish I could give more detailed logs of the commands that have run, but the output is long scrolled passed except for what gets logged to syslog and my memory is not as detailed due to the timeframe this has occurred over. Any help is greatly appreciated!

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  • I am starting to think that Prevx.com isnt a legit site...but heres my long-winded question

    - by cop1152
    I apologize in advance for the long-winded post. I posted it all because I believe its informative and may be useful. Also, I posted my question at the end. Moments ago I was RDC to a file server in my home (from inside my home). I had opened Firefox and Googled for a manufacturers website. Immediately after clicking the link, Firefox abruptly closed. This seemed odd to me to so I checked the running processes and discovered d.exe, e.exe, and f.exe running. I Googled these processes on a different machine and found them belonging to a key-logger/screen-capturer/trojan called defender.exe, which according to the Prevx lives in c:\documents and settings\user\local settings\temp. (Prevx link http://www.prevx.com/filenames/147352809685142526-X1/DEFENDER32.EXE.html) Simultaneously, an obviously-spoofed Windows Firewall popup appeared on the server asking me to click ‘yes’ to update Windows Firewall. At this time I ended all rogue processes, emptied the temp folder, removed defender.exe from startup, and checked my registry and a few other locations. Before deleting Defender.exe I noted that it was created moments ago, just before Firefox crashed. I believe that I was ‘almost’ infected with this malware. I believe that it needed me to click the phony popup in order to complete infection because it wasn’t allowed to execute processes from the temp folder. After cleaning the machine, I restarted it and have been monitoring it for over an hour. I am debating on whether or not to restore the Windows partition (a separate physical drive from the data) or to just watch it for awhle. I should mention that, because of the specs on this machine, I do not run antivirus software, but I know it well and inspect it regularly. It is a very old Compaq with a 400mhz processer and 512mb of ram. I have a static IP and the server is in the DMZ running an FTP client and some HTTP server software. All files transferred to and stored on this machine are scanned for malware before transferring. Usually the machine only runs 19 processes and performs pretty well for its intended purpose. I posted the story so that you could be aware of a possible new piece of malware and how it acts, but I also have a question or two. First, over the last few months I have noticed that PREVX is listed at the top of most of my Google searches when researching malware, especially for new or obscure malware…and they always want you to purchase something. I don’t think they are one of the top AV companies, so it seems odd that they are always the top Google result. Does anyone have any experience with any of their products? Also, what sites do you rely on for malware researching? Recently, I have found it difficult to find good info because of HijackThis-logs and other deadend info cluttering up my searches. And lastly, besides antivirus, third-party firewall, etc, what settings would you use to lock down a machine to make it more secure in instances where a stubborn admin like myself refuses to run AV? Thanks.

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  • linux raid 1: right after replacing and syncing one drive, the other disk fails - understanding what is going on with mdstat/mdadm

    - by devicerandom
    We have an old RAID 1 Linux server (Ubuntu Lucid 10.04), with four partitions. A few days ago /dev/sdb failed, and today we noticed /dev/sda had pre-failure ominous SMART signs (~4000 reallocated sector count). We replaced /dev/sdb this morning and rebuilt the RAID on the new drive, following this guide: http://www.howtoforge.com/replacing_hard_disks_in_a_raid1_array Everything went smooth until the very end. When it looked like it was finishing to synchronize the last partition, the other old one failed. At this point I am very unsure of the state of the system. Everything seems working and the files seem to be all accessible, just as if it synchronized everything, but I'm new to RAID and I'm worried about what is going on. The /proc/mdstat output is: Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md3 : active raid1 sdb4[2](S) sda4[0] 478713792 blocks [2/1] [U_] md2 : active raid1 sdb3[1] sda3[2](F) 244140992 blocks [2/1] [_U] md1 : active raid1 sdb2[1] sda2[2](F) 244140992 blocks [2/1] [_U] md0 : active raid1 sdb1[1] sda1[2](F) 9764800 blocks [2/1] [_U] unused devices: <none> The order of [_U] vs [U_]. Why aren't they consistent along all the array? Is the first U /dev/sda or /dev/sdb? (I tried looking on the web for this trivial information but I found no explicit indication) If I read correctly for md0, [_U] should be /dev/sda1 (down) and /dev/sdb1 (up). But if /dev/sda has failed, how can it be the opposite for md3 ? I understand /dev/sdb4 is now spare because probably it failed to synchronize it 100%, but why does it show /dev/sda4 as up? Shouldn't it be [__]? Or [_U] anyway? The /dev/sda drive now cannot even be accessed by SMART anymore apparently, so I wouldn't expect it to be up. What is wrong with my interpretation of the output? I attach also the outputs of mdadm --detail for the four partitions: /dev/md0: Version : 00.90 Creation Time : Fri Jan 21 18:43:07 2011 Raid Level : raid1 Array Size : 9764800 (9.31 GiB 10.00 GB) Used Dev Size : 9764800 (9.31 GiB 10.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:27:33 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : a3b4dbbd:859bf7f2:bde36644:fcef85e2 Events : 0.7704 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 17 1 active sync /dev/sdb1 2 8 1 - faulty spare /dev/sda1 /dev/md1: Version : 00.90 Creation Time : Fri Jan 21 18:43:15 2011 Raid Level : raid1 Array Size : 244140992 (232.83 GiB 250.00 GB) Used Dev Size : 244140992 (232.83 GiB 250.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:39:06 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : 8bcd5765:90dc93d5:cc70849c:224ced45 Events : 0.1508280 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 18 1 active sync /dev/sdb2 2 8 2 - faulty spare /dev/sda2 /dev/md2: Version : 00.90 Creation Time : Fri Jan 21 18:43:19 2011 Raid Level : raid1 Array Size : 244140992 (232.83 GiB 250.00 GB) Used Dev Size : 244140992 (232.83 GiB 250.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:46:44 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : 2885668b:881cafed:b8275ae8:16bc7171 Events : 0.2289636 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 19 1 active sync /dev/sdb3 2 8 3 - faulty spare /dev/sda3 /dev/md3: Version : 00.90 Creation Time : Fri Jan 21 18:43:22 2011 Raid Level : raid1 Array Size : 478713792 (456.54 GiB 490.20 GB) Used Dev Size : 478713792 (456.54 GiB 490.20 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 3 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:19:20 2013 State : clean, degraded Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 Number Major Minor RaidDevice State 0 8 4 0 active sync /dev/sda4 1 0 0 1 removed 2 8 20 - spare /dev/sdb4 The active sync on /dev/sda4 baffles me. I am worried because if tomorrow morning I have to replace /dev/sda, I want to be sure what should I sync with what and what is going on. I am also quite baffled by the fact /dev/sda decided to fail exactly when the raid finished resyncing. I'd like to understand what is really happening. Thanks a lot for your patience and help. Massimo

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  • Removing expired certificates from LDS (new ver of ADAM)

    - by jonthebrewer
    Hi all. This is my situation: We are in the process of replacing a certificate store currently hosted on Sun's iPlanet with Microsoft's Lightweight Directory Services (new version of ADAM with Server 2008). These certificates have been imported into LDS into an application partition (say o=myorg, C=AU). Under this structure I have around 40,000 OU's each one representing a customer under each customers OU are one or more user (iNetOrg) objects (around 60,000 in all). In each user are one or more certificates in the UserCertificate attribute. A combination of in-house written application code and proprietory PKI code reads and publishes these certficates to validate financial transactions. As the LDAP path of the certificates is stored within the customer certificates (and within the application code) and there is zero appetite for changing any of the code, I have had to pick up the iPlanet directory as a whole and dump it in LDS in the same structure. (I will not be using or hosting a Microsoft CA, just implementing an LDAP compliant directory to host these certificates) We have fully tested the application using the data in LDS and everything works fine - here is my dilema and question (finally, phew!) There was no process put in place for removing revoked or expired certificates, consequently the vast majority of the data is completely useless, the system has been running for about 8 years! I have done a quick analysis and I estimate that at least 80% of the data is no longer valid. As I am taking on responsibility for managing the directory I would like to start with a clean directory. Does anyone have any idea how I can cleanup these expired certificates. I am not a highly experienced scripter but have some background in VB. I have been researching the use of CAPICOM and have a feeling this may be able to be used but in exactly what way I am not sure?? I would prefer to write a script that I could specify an expiration date (say any certs that expired prior to 2010) then run against the LDS paritition. This way I can reuse the script periodically to cleanup the directory (as mentioned above - I have no way to adjust the applications that are writing the certs, this is with a third party). Another, less attractive, alternative is to massage the LDIF file (2.7 million lines!) to rip the certs out prior to the import Any help and advice MUCH appreciated. Cheers Jon

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  • JBoss EJB Bean not bound

    - by portoalet
    Hi, I have the following error Exception in thread "main" javax.naming.NameNotFoundException: CounterBean not bound trying to access an EJB JAR CounterBean.jar deployed on JBoss5 from a client application outside the Application Server. From the Jboss log, it looks like it does not have a global JNDI name? Is this ok? What have I done wrong? JBoss log: 13:50:39,669 INFO [JBossASKernel] Created KernelDeployment for: Counter.jar 13:50:39,672 INFO [JBossASKernel] installing bean: jboss.j2ee:jar=Counter.jar,name=CounterBean,service=EJB3 13:50:39,672 INFO [JBossASKernel] with dependencies: 13:50:39,672 INFO [JBossASKernel] and demands: 13:50:39,673 INFO [JBossASKernel] partition:partitionName=DefaultPartition; Required: Described 13:50:39,673 INFO [JBossASKernel] jboss.ejb:service=EJBTimerService; Required: Described 13:50:39,673 INFO [JBossASKernel] and supplies: 13:50:39,673 INFO [JBossASKernel] jndi:CounterBean 13:50:39,673 INFO [JBossASKernel] Added bean(jboss.j2ee:jar=Counter.jar,name=CounterBean,service=EJB3) to KernelDeployment of: Counte r.jar 13:50:39,712 INFO [SessionSpecContainer] Starting jboss.j2ee:jar=Counter.jar,name=CounterBean,service=EJB3 13:50:39,727 INFO [EJBContainer] STARTED EJB: com.don.CounterBean ejbName: CounterBean 13:50:39,732 INFO [JndiSessionRegistrarBase] Binding the following Entries in Global JNDI: The client code is: public static void main(String[] args) throws NamingException, InterruptedException { InitialContext ctx = new InitialContext(); Counter s = (Counter)ctx.lookup("CounterBean/remote"); for(int i = 0; i < 100; i++ ) { s.printCount(i); Thread.sleep(1000); } } Error message: java -Djava.naming.provider.url=jnp://123.123.123.123:1099 -Djava.naming.factory.initial=org.jnp.interfaces.NamingContextFactory com.don.Client Exception in thread "main" javax.naming.NameNotFoundException: CounterBean not bound at org.jnp.server.NamingServer.getBinding(NamingServer.java:771) at org.jnp.server.NamingServer.getBinding(NamingServer.java:779) at org.jnp.server.NamingServer.getObject(NamingServer.java:785) at org.jnp.server.NamingServer.lookup(NamingServer.java:396) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:305) at sun.rmi.transport.Transport$1.run(Transport.java:159) at java.security.AccessController.doPrivileged(Native Method) at sun.rmi.transport.Transport.serviceCall(Transport.java:155) at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:619) at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:255) at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:233) at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:142) at org.jnp.server.NamingServer_Stub.lookup(Unknown Source) at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:726) at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:686) at javax.naming.InitialContext.lookup(InitialContext.java:392) at com.don.Client.main(Client.java:10)

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  • Connecting to Active Directory Application Mode from Perl

    - by Khurram Aziz
    I am trying to connect to Active Directory Application Mode instance. The instance is conenctable from third party LDAP clients like Softerra LDAP Browser. But I am getting the following error when connecting from Perl Net::LDAP=HASH(0x876d8e4) sending: Net::LDAP=HASH(0x876d8e4) received: 30 84 00 00 00 A7 02 01 02 65 84 00 00 00 9E 0A 0........e...... 01 01 04 00 04 84 00 00 00 93 30 30 30 30 30 34 ..........000004 44 43 3A 20 4C 64 61 70 45 72 72 3A 20 44 53 49 DC: LdapErr: DSI 44 2D 30 43 30 39 30 36 32 42 2C 20 63 6F 6D 6D D-0C09062B, comm 65 6E 74 3A 20 49 6E 20 6F 72 64 65 72 20 74 6F ent: In order to 20 70 65 72 66 6F 72 6D 20 74 68 69 73 20 6F 70 perform this op 65 72 61 74 69 6F 6E 20 61 20 73 75 63 63 65 73 eration a succes 73 66 75 6C 20 62 69 6E 64 20 6D 75 73 74 20 62 sful bind must b 65 20 63 6F 6D 70 6C 65 74 65 64 20 6F 6E 20 74 e completed on t 68 65 20 63 6F 6E 6E 65 63 74 69 6F 6E 2E 2C 20 he connection., 64 61 74 61 20 30 2C 20 76 65 63 65 00 __ __ __ data 0, vece.` My directory structure is Partition: CN=Apps,DC=MyCo,DC=COM User exists as CN=myuser,CN=Apps,DC=MyCo,DC=COM I have couple of other entries of the custom class which I am interested to browse; those instances appear fine in ADSI Edit, Softerra LDAP Browser etc. I am new to Perl....My perl code is #!/usr/bin/perl use Net::LDAP; $ldap = Net::LDAP->new("127.0.0.1", debug => 2, user => "CN=myuser,CN=Apps,DC=MyCo,DC=COM", password => "secret" ) or die "$@"; $ldap->bind(version => 3) or die "$@"; print "Connected to ldap\n"; $mesg = $ldap->search( filter => "(objectClass=*)" ) or die ("Failed on search.$!"); my $max = $mesg->count; print "$max records found!\n"; for( my $index = 0 ; $index < $max ; $index++) { my $entry = $mesg->entry($index); my $dn = $entry->dn; @attrs = $entry->attributes; foreach my $var (@attrs) { $attr = $entry->get_value( $var, asref => 1 ); if ( defined($attr) ) { foreach my $value ( @$attr ) { print "$var: $value\n"; } } } } $ldap->unbind();

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  • Reliable way of generating unique hardware ID

    - by mr.b
    Question: what's the best way to accomplish following. I have to come up with unique ID for each networked client, such that: it (ID) should persist once client software is installed on target computer, and should continue to persist if software is re-installed on same computer and same OS installment, it should not change if hardware configuration is modified in most ways (except changing the motherboard) When hard drive with client software installed is cloned to another computer with identical hardware configuration (or, as similar as possible), client software should be aware of that change. A little bit of explanation and some back-story: This question is basically age old question that also touches topic of software copy-protection, as some of mechanisms used in that area are mentioned here. I should be clear at this point that I'm not looking for a copy-protection scheme. Please, read on. :) I'm working on a client-server software that is supposed to work in local network. One of problems I have to solve is to identify each unique client in network (not so much of a problem), so that I can apply certain attributes to every specific client, retain and enforce those attributes during deployment lifetime of a specific client. While I was looking for a solution, I was aware of following: Windows activation system uses some kind of heavy fingerprinting mechanism, that is extremely sensitive to hardware modifications, Disk imaging software copies along all Volume IDs (tied to each partition when formatted), and custom, uniquely generated IDs during installation process, during first run, or in any other way, that is strictly software in its nature, and stored in registry or on hard drive, so it's very easy to confuse two Obvious choice for this kind of problem would be to find out BIOS identifiers (not 100% sure if this is unique through identical motherboard models, though), as that's the only thing I can rely on, that isn't duplicated, transferred by cloning, and that can't be changed (at least not by using some user-space program). Everything else fails as either being not reliable (MAC cloning, anyone?), or too demanding (in terms that it's too sensitive to configuration changes). Am I missing something obvious here? Sub-question that I'd like to ask is, am I doing it correctly, architecture-wise? Perhaps there is a better tool for task that I have to accomplish... Another approach I had in mind is something similar to handshake mechanism, where server maintains internal lookup table of connected client IDs (which can be even completely software-based and non-unique at any given moment), and tells client to come up with different ID during handshake, if duplicate ID is provided upon connection. That approach, unfortunately, doesn't play nicely with one of requirements to tie attributes to specific client during lifetime.

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  • Finding minimum cut-sets between bounded subgraphs

    - by Tore
    If a game map is partitioned into subgraphs, how to minimize edges between subgraphs? I have a problem, Im trying to make A* searches through a grid based game like pacman or sokoban, but i need to find "enclosures". What do i mean by enclosures? subgraphs with as few cut edges as possible given a maximum size and minimum size for number of vertices for each subgraph that act as a soft constraints. Alternatively you could say i am looking to find bridges between subgraphs, but its generally the same problem. Given a game that looks like this, what i want to do is find enclosures so that i can properly find entrances to them and thus get a good heuristic for reaching vertices inside these enclosures. So what i want is to find these colored regions on any given map. My Motivation The reason for me bothering to do this and not just staying content with the performance of a simple manhattan distance heuristic is that an enclosure heuristic can give more optimal results and i would not have to actually do the A* to get some proper distance calculations and also for later adding competitive blocking of opponents within these enclosures when playing sokoban type games. Also the enclosure heuristic can be used for a minimax approach to finding goal vertices more properly. A possible solution to the problem is the Kernighan-Lin algorithm: function Kernighan-Lin(G(V,E)): determine a balanced initial partition of the nodes into sets A and B do A1 := A; B1 := B compute D values for all a in A1 and b in B1 for (i := 1 to |V|/2) find a[i] from A1 and b[i] from B1, such that g[i] = D[a[i]] + D[b[i]] - 2*c[a][b] is maximal move a[i] to B1 and b[i] to A1 remove a[i] and b[i] from further consideration in this pass update D values for the elements of A1 = A1 / a[i] and B1 = B1 / b[i] end for find k which maximizes g_max, the sum of g[1],...,g[k] if (g_max > 0) then Exchange a[1],a[2],...,a[k] with b[1],b[2],...,b[k] until (g_max <= 0) return G(V,E) My problem with this algorithm is its runtime at O(n^2 * lg(n)), i am thinking of limiting the nodes in A1 and B1 to the border of each subgraph to reduce the amount of work done. I also dont understand the c[a][b] cost in the algorithm, if a and b do not have an edge between them is the cost assumed to be 0 or infinity, or should i create an edge based on some heuristic. Do you know what c[a][b] is supposed to be when there is no edge between a and b? Do you think my problem is suitable to use a multi level problem? Why or why not? Do you have a good idea for how to reduce the work done with the kernighan-lin algorithm for my problem?

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  • Best way to handle multiple tables to replace one big table in Rails? (e.g. 'Books1', 'Books2', etc.

    - by mikep
    Hello, I've decided to use multiple tables for an entity (e.g. Books1, Books2, Books3, etc.), instead of just one main table which could end up having a lot of rows (e.g. just Books). I'm doing this to try and to avoid a potential future performance drop that could come with having too many rows in one table. With that, I'm looking for a good way to handle this in Rails, mainly by trying to avoid loading a bunch of unused associations. (I know that I could use a partition for this, but, for now, I've decided to go the 'multiple tables' route.) Each user has their books placed into a specific table. The actual book table is chosen when the user is created, and all of their books go into the same table. I'm going to split the adds across the tables. The goal is to try and keep each table pretty much even -- but that's a different issue. One thing I don't particularly want to have is a bunch of unused associations in the User class. Right now, it looks like I'd have to do the following: class User < ActiveRecord::Base has_many :books1, :books2, :books3, :books4, :books5 end class Books1 < ActiveRecord::Base belongs_to :user end class Books2 < ActiveRecord::Base belongs_to :user end class Books3 < ActiveRecord::Base belongs_to :user end I'm assuming that the main performance hit would come in terms of memory and possibly some method call overhead for each User object, since it has to load all of those associations, which in turn creates all of those nice, dynamic model accessor methods like User.find_by_. But for each specific user, only one of the book tables would be usable/applicable, since all of a user's books are stored in the same table. So, only one of the associations would be in use at any time and any other has_many :bookX association that was loaded would be a waste. For example, with a user.id of 2, I'd only need books3.find_by_author('Author'), but the way I'm thinking of setting this up, I'd still have access to Books1..n. I don't really know Ruby/Rails does internally with all of those has_many associations though, so maybe it's not so bad. But right now I'm thinking that it's really wasteful, and that there may just be a better, more efficient way of doing this. So, a few questions: 1) Is there's some sort of special Ruby/Rails methodology that could be applied to this 'multiple tables to represent one entity' scheme? Are there any 'best practices' for this? 2) Is it really bad to have so many unused has_many associations for each object? Is there a better way to do this? 3) Does anyone have any advice on how to abstract the fact that there's multiple book tables behind a single books model/class? For example, so I can call books.find_by_author('Author') instead of books3.find_by_author('Author'). Thank you!

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