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  • Comparing 2 (or 3 Files If Possible) "Line By Line"

    - by PythEch
    I want to find out the differences of 2 (or 3 files if possible) line by line. Diff utils can do this, however it gives inaccurate results. Because, 2 files have exact number of lines which is "134". But diff gives me "Added Lines" and "Removed Lines". However this is wrong, they have exact the same number of lines, there is no added or removed lines. The text files which I want to find differences of them, have only numbers written, maybe that's why that algortihm fails. I couldn't find any option to prevent that, however I may be wrong, I mean there should be an option for that, but again, I couldn't find. This is what I get (5am.txt vs 6am.txt, there is a huge problem): This is what I want (6am.txt vs 7am.txt, still has problems): But, first the first image still has this problem, at the last lines. Edit: After I figured out that there is no utility to do this, I handled myself. I almost did the same thing as what RedGrittyBrick have done. This script imitates diff utility so I (or you) can use it with diff2html. To use it with diff2html, just change line diff_stdout = os.popen("diff %s" % string.join(argv[1:]), "r") to diff_stdout = os.popen("script.py %s" % string.join(argv[1:]), "r") and name this script whatever you want: import sys f1=open(sys.argv[1],"r") f1_read=f1.readlines() f1.close() f2=open(sys.argv[2],"r") f2_read=f2.readlines() f2.close() changed={} first_c = "" for n in range(len(f1_read)): if f1_read[n]!=f2_read[n]: if first_c == "": first_c=n+1 changed[first_c]=n+1 else: first_c="" #Let's imitate diff-utils... for (x, y) in changed.items(): print "%d,%dc%d,%d" % (x,y,x,y) for i in range(x,y+1): sys.stdout.write("< %s" % f1_read[i-1]) print "---" for i in range(x,y+1): sys.stdout.write("> %s" % f2_read[i-1]) Final results:

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  • How can I proxy multiple LDAP servers, and still have grouping of users on the proxy?

    - by Chris
    I have 2 problems that I'm hoping to find a common solution to. First, I need to find a way to have multiple LDAP servers (Windows AD's across multiple domains) feed into a single source for authentication. This is also needed to get applications that can't natively talk to more than one LDAP server to work. I've read this can be done with Open LDAP. Are there other solutions? Second, I need to be able to add those users to groups without being able to make any changes to the LDAP servers I'm proxying. Lastly, this all needs to work on Windows Server 2003/2008. I work for a very large organization, and to create multiple groups and have large numbers of users added to, moved between, and removed from them is no small task. This normally requires tons of paperwork and a lot of time. Time is the one thing we don't normally have; dodging the paperwork is just a plus. I have very limited experience in all this, so I'm not even sure what I'm asking will make sense. Atlassian Crowd comes close to what we need, but falls short of having it's own LDAP front end. Can anyone provide any advice or product names? Thanks for any help you can provide.

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  • Need help trying to diagnose Symmetrix SAN performance issues

    - by arcain
    I am helping to benchmark hardware for a new SQL Server instance, and the volume presented to the OS for the data files is carved from a set of spindles on a Symmetrix SAN. The server has yet to have SQL Server installed, so the only activity on the box is our benchmarking. Now, our storage engineers say that this volume and it's resources are dedicated to our new server (I don't have access to see the actual SAN config) however the performance benchmarks are troubling. For example, the numbers look good until suddenly, and randomly, we see in our IO benchmarking tool wait times of 100 seconds, and disk queue lengths of 255 in perfmon. This SAN has an 8 GB cache, plus there are other applications besides ours that use the SAN. I'm wondering if (even though the spindles for our volumes should be dedicated to us) the cache may be getting hammered during the performance testing, or perhaps the spindles our volumes are on aren't really dedicated to us. We're not getting much traction from our storage engineers in helping us track down the problem, so if anybody has experience with diagnosing a problem like this and would like to share insights and troubleshooting methodologies, I'd appreciate it.

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  • How does VirtualBox's memory usage work?

    - by DrFredEdison
    I've been running several VM's with VirtualBox, and the memory usage reported from various perspectives, and I'm having trouble figuring how much memory my VMs actually use. Here is an example: I have a VM running Windows 7 (as the Guest OS) on my windows XP Host machine. The Host Machine Has 3 GB of RAM The Guest VM is setup to have a base memory of 1 GB If I run Task Manger on the Guest OS, I see memory usage of 430 MB If I run Task Manger on the host OS, I see 3 processes that seem to belong to VirtualBox: VirtualBox.exe (1), using 60 MB of memory (This one seems to have the most CPU usage) VirtualBox.exe (2), using 20 MB of memory VBoxSvc.exe, using 11.5 MB of memory While running the VM, the Host OS's memory usage is about 2 GB When I shut down the VM, the Host OS's it goes back to memory usage goes down to about 900 MB So clearly, there are some huge differences here. I really don't understand how the GuestOS can use 400+ MB, while the Host OS only shows about 75 MB allocated to the VM. Are there other processes used by VirtualBox that aren't as obviously named? Also, I'd like to know if I run a machine with 1 GB, is that going to take 1 GB away from my host OS, or only the amount of memory the Guest machine is currently using? update Somene expressed distrust over my memory usage numbers, and I'm not sure if that distrust was directed at me, or my Host OS's Task Manager's reporting (which is perhaps the culprit), but for any skeptics, here is a screenshot of those processes on the host machine:

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  • How to diagnose storage system scaling problems?

    - by Unknown
    We are currently testing the maximum sequential read throughput of a storage system (48 disks total behind two HP P2000 arrays) connected to HP DL580 G7 running RHEL 5 with 128 GB of memory. Initial testing has been mainly done by running DD-commands like this: dd if=/dev/mapper/mpath1 of=/dev/null bs=1M count=3000 In parallel for each disk. However, we have been unable to scale the results from one array (maximum throughput of 1.3 GB/s) to two (almost the same throughput). Each array is connected to a dedicated host bust adapter, so they should not be the bottleneck. The disks are currently in JBOD configuration, so each disk can be addressed directly. I have two questions: Is running multiple DD commands in parallel really a good way to test maximum read throughput? We have noticed very high SWAPIN-% numbers in iotop, which I find hard to explain because the target is /dev/null How shoud we proceed in trying to find the reason for the scaling problem? Do you thing the server itself is the bottleneck here, or could there be some linux parameters that we have overlooked?

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  • How can I redirect/forward all the UDP/TCP traffic on one interface to another interface in OpenWrt

    - by Sina Sou
    I am new to networking and I have a measurement device (D) that periodically sends all its readings over few UDP multicast sockets (with different multicast IP addresses and different port numbers). That device even listens to a TCP socket simultaneously to modify its configuration on port 7234. Since the device has just a Ethernet interface for communication and I want to make it work wireless, I decided to use a very small wireless open-wrt based router that attaches to the device (D) and redirect/forward all the network traffic(Both UDP/TCP) to the router wireless interface. In order to simplify the problem assume that the Device (D) establishes following sockets (at the same time) UM_SOCK1: UDP mcast socket on 239.1.2.3 port# 50620 UM_SOCK2: UDP mcast socket on 239.1.2.4 port# 50640 TC_SOCK3: TCP DHCP/STATIC ip address 192.168.1.200 port 7234 And (D) is connected to Open-Wrt router (R) via interface en01 (Ethernet) the router has it own wireless interface on (wlan0) I want all the traffic from interface pass through wlan01 and vice versa (bi-directional) en01 <---- wlan01 What would be the minimum iptables or ... commands that I need to make this possible? Even I am wondering if traffic directing can be made easier like if the direction is not going to be based on IP addresses(not desired if the device is connected via DHCP) I would rather redirection to be Interface(en0) based or on MAC address (The best solution since my device has unique MAC address)? Thanks

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  • Why is MySQL table_cache full but never used

    - by Jeremy Clarke
    I have been using the tuning-primer.sh script to tune my my.cnf settings. I have most things working well but the part about TABLE CACHE makes no sense: TABLE CACHE Current table_cache value = 900 tables. You have a total of 0 tables You have 900 open tables. Current table_cache hit rate is 1% , while 100% of your table cache is in use. You should probably increase your table_cache When I do SHOW STATUS; I get the following table-related numbers: Open_tables = 900 Opened_tables = 0 It seems like something is going wrong. I have some extra memory I could use on increasing the table_cache size, but my sense is that the 900 tables already available aren't doing anything, and increasing it will just waste more energy. Why might this be happening? Are there other settings that could cause all my table_cache slots to be used even though there are no hits to them? I have 150 max connections and probably no more than 4 tables per join, FWIW. Here is the tuner script output for temp tables, which I've also been tuning: TEMP TABLES Current max_heap_table_size = 90 M Current tmp_table_size = 90 M Of 11032358 temp tables, 40% were created on disk Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables. Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables.

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  • SQL Server performance on VSphere 4.0

    - by Charles
    We are having a performance issue that we cannot explain with our VMWare environment and I am hoping someone here may be able to help. We have a web application that uses a databases backend. We have an SQL 2005 Cluster setup on Windows 2003 R2 between a physical node and a virtual node. Both physical servers are identical 2950's with 2x Xeaon x5460 Quad Core CPUs and 64GB of memory, 16GB allocated to the OS. We are utilizing an iSCSI San for all cluster disks. The problem is this, when utilizing the application under a repeated stress testing that adds CPUs to the cluster nodes, the Physical node scales from 1 pCPU to 8 pCPUs, meaning we see continued performance increases. When testing the node running Vsphere, we have the expected 12% performance hit for being virtual but we still scale from 1 vCPU to 4 vCPUs like the physical but beyond this performance drops off, by the time we get to 8 vCPUs we are seeing performance numbers worse than at 4 vCPUs. Again, both nodes are configured identically in terms of hardware, Guest OS, SQL Configurations etc and there is no traffic other than the testing on the system. There are no other VMs on the virtual server so there should be no competition for resources. We have contacted VMWare for help but they have not really been any suggesting things like setting SQL Processor Affinity which, while being helpful would have the same net effect on each box and should not change our results in the least. We have looked at all of VMWare's SQL Tuning guides with regards to VSphere with no benefit, please help!

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  • ixgbe driver: Limit the max number of cores

    - by Shellex Wai
    I have a Linux workstation with 48 cores and runs ixgbe driver for fiber interface. And I have to test a project name Netmap on it. NetMap is a high performance network framework for high speed interfaces, which has been ported to Linux recently. For some reasons, I must try it on the machine. So I compile it and follow the instructions to run the test problems, but it doesn't work. I check dmesg and it says: [10399.085736] 794.159015 netmap_set_ringid [486] ringid o4o1 set to all 48 HW RINGS [10399.085742] 794.282011 netmap_obj_malloc [220] netmap_if request size 816 too large I asked the author of netmap for help. He told me that I have too many cores in the machine and it should work if I tell ixgbe use less cores (2 to 4 is ok). I am not familiar to driver development and I don't know how to limit the ring numbers by passing arguments to ixgbe driver. So I check the spec from intel's website but found nothing about it. So I come here for more helps. Thank you.

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  • Syncing two sheets, while being able to hide different data

    - by Joshua
    I'm pretty new to excel- so please bear with me. I have created a spreadsheet to organize gear by serial numbers and by who has it. This list is getting updated multiple times daily as gear shuffles regularly. I have gear that is assigned and unassigned. On the main sheet I have all the data, the way I want it to be organized. What I'm trying to do is duplicate this sheet, so that both sheets automatically keep the same data at all times, but on the first sheet I can hide all the unassigned gear, and view only the assigned gear, and then be able to narrow it down in groups using the hide function heavily. On the second sheet I want to be able to hide all of the assigned gear, and all the columns of gear that have no unassigned gear. End result will be that as gear is moved between individuals or is unassigned entirely, I make that adjustment on one sheet and the data stays the same on both, but the way I view that same sheet is different on both. If I'm making no sense just let me know and I'll try to explain again more clearly. Thanks

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  • Formula-based Excel page headers

    - by Jake Krohn
    I'm using the "Rows to repeat at top" function in Excel's "Page Setup" dialog to ensure that a multi-row header block appears on every printed page of my worksheet. However, I'd like to be able to change certain bits of the header based on the content of the current page. I would simply like to display the value of one cell in the first row that is printed on the page. If this is my header: Section: xx And the data looks like this (columns are Section and Name): 1 Foo 1 Bar 2 Baz I want the "xx" in the header to be "1". If, further down on the next page, the value in the Section column is "3", I want that printed in the header of the next page. I originally thought that using the "OFFSET" function might help, e.g. ="Section: "&OFFSET(A2, 1, 0) But it only shows the offset from the original placement of the header, thus only working on page 1. The end document is a PDF, so right now I'm able to go back in with the "TouchUp Text Tool" in Acrobat and add the numbers page by page. But it gets to be a tedious process with 70+ page reports. Anyone have any better ideas that don't require me mucking up the original Excel document with inserted headers every N lines? This is Excel 2008 for Mac, if it makes a difference.

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  • Why is my server performance degrading to the point of stopping, periodically?

    - by Pascal Aschwanden
    So, once in a while, I see in firebug that a request takes over 15 or even 60 seconds to respond and sometimes never. Here is what I've ruled out: It's not the CPU, cuz every time I check the Server load its less then 6 for all 3 numbers It's not the memory, because thats fairly low too, less the 50% It's not the I/O anymore, because I've seen the graphs that Joyent sent back to me when I requested them, and they show less then 3MB of I/O (mostly all read). It's not the SQL performance - I've profiled every last SQL command that runs, and they're all (99.9% of them anyway) running in less then 30ms, most run in less then 5ms. Oh and I've been profiling all the script execution times, and even the when the problem occurs, the script always manages to finish in 50ms or less (that's 1 / 20th of a second ). Now, I do run alot of ajax calls. 1 every 2 seconds per user and I have 300 DAU+. But, even if all 300 are playing simultaneously, thats still only 150 calls per second max. The only other thing I can think of is that one of my neighbors is funky. The problem is highly intermittent. 99% of the time it works perfectly and there's excellent performance. but 99%+ is not good enough. Eventually the performance gets so bad I have to restart the server, at which point everything is fine again. I've done this about 4 times now. Any ideas? Note: this is on joyent, vps, intro package 256mb of ram with bursting. here are the mysql dump info: Traffic ø per hour Received 18 MiB 29 MiB Sent 134 MiB 221 MiB Total 151 MiB 251 MiB Connections ø per hour % max. concurrent connections 5 --- --- Failed attempts 0 0.00 0.00% Aborted 0 0.00 0.00% Total 9,418 15.59 k 100.00%

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  • F2 in Paste mode

    - by dotancohen
    Vim has a terrific paste mode, in which abbreviations and mappings are ignored. Frustratingly, even keys that do not map to pastable ASCII characters, such as the function keys, are pasted literally. For instance the key F2 is pasted as <F2>. Is there anyway around this? Note that pastetoggle can in fact be mapped to a function key to easily leave paste mode, however the function that I am writing changes other values when entering or leaving paste mode (such as enabling or disabling line numbers and other things). Therefore I would really like to find a workaround. For reference, here is the current version of the function (that gets stuck in paste mode): iab if if<Space>(<Space>{{<Esc>kA<Left><Left><Left><Left><C-R>=Eatchar('\s')<CR> " Triple-toggle Insert Modes: coding, prose, and paste let g:insertModeGlobal=1 function! Te() if g:insertModeGlobal==3 " Was in paste insert mode, go to coding insert mode set nu set nopaste let g:insertModeGlobal=4 endif if g:insertModeGlobal==2 " Was in prose insert mode, go to paste insert mode set nolinebreak nnoremap j j nnoremap k k nnoremap gj gj nnoremap gk gk set relativenumber execute ":Signs" iab if if<Space>(<Space>{{<Esc>kA<Left><Left><Left><Left><C-R>=Eatchar('\s')<CR> set nonu set paste let g:insertModeGlobal=3 endif if g:insertModeGlobal==1 " Was in coding insert mode, go to prose insert mode set linebreak nnoremap j gj nnoremap k gk nnoremap gj j nnoremap gk k set number execute ":DisableSigns" iab if if let g:insertModeGlobal=2 endif if g:insertModeGlobal==4 let g:insertModeGlobal=1 endif endfunction

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  • How may I retrieve data from an Excel table based on a variable number of criteria?

    - by Eshwar
    I have the following salary data for example: Country State 2012 2013 -> 2027 ======= ===== ==== ==== China Other 1000 1100 China Shanghai 1310 1400 China Tianjin 1450 1500 India Orissa 1500 1600 So now in another Excel sheet I would want an answer to one of the following questions: What is the salary in Shanghai for 2013? (Answer would be 1400) What is the salary in Hubei province for 2012? (Since it is not listed, use "Other" - 1000) What is the average salary in China for 2013? (Answer would be 1450) What is the highest salary in China for 2012? (Answer is Tianjin) So as in the above order of priority, I would like those numbers in another Excel sheet using some form of query. I considered PivotTables but I was wondering if there is another much better more efficient way of doing this? I imagine SQL is suited for this but I am not clued up on that. Some Excel functionality is much rather preferred. Also suggestions on an appropriate format of data for such queries would be appreciated.

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  • Why is my global security group being filtered out of my logon token?

    - by Jay Michaud
    While investigating the effects of filtered tokens on my file permissions, I noticed that one of my global security groups is being filtered in addition to the regular system-defined filtered groups. My Active Directory environment is a single-domain forest on the Windows Server 2003 functional level. I'll call the domain "mydomain.example.com". I am logged onto a Windows Server 2008 Enterprise Edition machine (not a domain controller) as a member of the "MYDOMAIN\Domain Admins" group and the "MYDOMAIN\MySecurityGroup" global security group (among others). When I run "whoami /groups" from an elevated command prompt, I see the full list of groups to which my account belongs as expected. When I run "whoami /groups" from a regular, non-elevated command prompt, I see the same list of groups, but the following groups are described as "Group used for deny only". BUILTIN\Administrators MYDOMAIN\Schema Admins MYDOMAIN\Offer Remote Assistance Helpers MYDOMAIN\MySecurityGroup Numbers 1 through 3 above are expected based on Microsoft documentation; number 4 is not. The "MYDOMAIN\MySecurityGroup" global security group is a group that I created. It contains three non-built-in global security groups, and these security groups contain only non-built-in user accounts. (That is, I created all of the accounts and groups that are members of the "MYDOMAIN\MySecurityGroup" global security group.) There are other, similar groups of which my account is a member that are not being filtered out of my logon token, and this group is not granted any specific user rights in the security settings of this computer or in Group Policy. What would cause this one group to be filtered out of my logon token?

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  • Difficult to point-and-click target with Apple Magic Trackpad?

    - by Andrew Swift
    My Magic Trackpad is great for most things involving dragging and gestures, but for simple point-and-click use it is starting to get really annoying. For example, my bank has a numeric code that I need to enter from a visual grid on the screen, by clicking on the six numbers in order. To do this is quite difficult with the Magic Trackpad. Idea 1: it is because when you start dragging on the touchpad, there is a brief delay before the mouse starts to move. The delay might be enough to screw up my anticipation of where the cursor is going to go. Idea 2: it may have to do with the cursor acceleration. If I move it a little, the cursor moves a little. If I move it a lot, it goes much faster. I have tried various settings in the preference pane, and although the cursor does move more or less quickly, it doesn't seem any more or less easy to hit a given target. As I am writing this post, I tried a brief experiment -- I chose a spot on the page (the bracket in the superuser logo) and tried to move the cursor there in one quick movement. It's extremely difficult, even though I've been using Macs and touchpads since 1999. There is something about the behavior of the trackpad that is making it impossible for me to learn how to accurately predict where the cursor will end up. Does anyone else have this problem?

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  • How to calculate unweighted averages in Excel PivotTable?

    - by yonatron
    I often make PivotTables in which each row contains a number of per-person average measures. I then want to look at the unweighted column average for each measure, and usually make some kind of chart from these. Because my individual cells are often averaged from different numbers of data points, the Grand Total row ends up being a weighted average, which I’m not interested in. So I usually make my own average row a few rows above the table to use for my charts. That’s not too much work, but there’s another problem. I often add a few more people’s worth of data to the PivotTables’ source, then refresh the tables. This means my average row needs to be updated to encompass more rows from the PivotTable. Not a huge deal with one table, but when I have lots of them across lots of sheets, I have to do find/replace on a whole bunch of formulas. So: is there a way to automatically get unweighted column averages in a PivotTable, such that when the table is refreshed, the averages don’t change locations and encompass the newly added (or removed) data Thanks

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  • Users getting 'flooded' with not read notifications (NRNs) for old emails and meeting requests

    - by Exile
    I'm being placed under quite a lot of pressure from senior management over a relatively trivial issue. Basically the vast majority of users are complaining that they receive not read notifications (NRNs) for old emails and meeting requests in large numbers multiple times a day. I know something strange is happening because some are delivered at silly times in the morning (i.e 3AM or 4AM). The problem I have is that these some of these NRNs are from meeting requests and messages that are 120 days old, so some users have deleted the original message so I don’t actually know if the NRN is from an email or meeting request. This is typical of what users receive as a NRN: From: Sender Sent: 23 March 2012 04:16 To: Recepient Subject: Not read: Accepted: Status update Your message To: Sender Subject: Accepted: Status update Sent: Wednesday, November 23, 2011 8:59:00 AM (UTC) Dublin, Edinburgh, Lisbon, London was deleted without being read on Friday, March 23, 2012 4:15:32 AM (UTC) Dublin, Edinburgh, Lisbon, London. ... From: Sender Sent: 18 March 2012 01:13 To: Recepient Subject: Not read: Gold delivery - Sourcing module Your message To: Sender Subject: Gold delivery - Sourcing module Sent: Friday, November 18, 2011 9:37:58 AM (UTC) Dublin, Edinburgh, Lisbon, London was deleted without being read on Sunday, March 18, 2012 1:12:37 AM (UTC) Dublin, Edinburgh, Lisbon, London. I have done a search and found the following: http://support.microsoft.com/kb/2544246 http://support.microsoft.com/kb/2471964 But we already installed 'Update Rollup 6 for Exchange Server 2010 Service Pack 1' back in December, so I am not sure what we can do to fix this?

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  • Difficult to point-and-click target with Apple Magic Trackpad?

    - by Andrew Swift
    My Magic Trackpad is great for most things involving dragging and gestures, but for simple point-and-click use it is starting to get really annoying. For example, my bank has a numeric code that I need to enter from a visual grid on the screen, by clicking on the six numbers in order. To do this is quite difficult with the Magic Trackpad. Idea 1: it is because when you start dragging on the touchpad, there is a brief delay before the mouse starts to move. The delay might be enough to screw up my anticipation of where the cursor is going to go. Idea 2: it may have to do with the cursor acceleration. If I move it a little, the cursor moves a little. If I move it a lot, it goes much faster. I have tried various settings in the preference pane, and although the cursor does move more or less quickly, it doesn't seem any more or less easy to hit a given target. As I am writing this post, I tried a brief experiment -- I chose a spot on the page (the bracket in the superuser logo) and tried to move the cursor there in one quick movement. It's extremely difficult, even though I've been using Macs and touchpads since 1999. There is something about the behavior of the trackpad that is making it impossible for me to learn how to accurately predict where the cursor will end up. Does anyone else have this problem?

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  • Why is only one Excel spreadsheet crippled, but others are fine?

    - by Dallas
    I have an inherited spreadsheet that I really don't want to rebuild at the moment. It's a simple small workbook that is small (< 200 rows that don't even reach to AA) and does nothing more than calculate some totals within the same worksheets. No macros, no external data sources, nothing beyond basic formatting of dates, numbers and strings. I see importing data from CSV/text has created many many workbook connections over time, but even if I delete them all (there were hundreds) it makes no difference in performance. Even clicking to simply change focus from cell to cell takes 10+ seconds, adorned by the spinning cursor and (Not Responding) appending to the title bar and the application locking up. The program seems to "recover" every time, but efficiency of editing this file is obviously seriously handicapped. All other files seem fine in Excel, and other programs have no apparent performance issues. I see Excel is chewing up CPU but I'm not sure how to narrow down what process or service is "clashing" with Excel. I tried the same file on other computers and performance is fine. If I turn off all start-up services and run only Excel, performance is restored... until I start using other programs and then it bogs down again. At this point, I would entertain almost any idea, theory or suggestion that helps pinpoint, solve or work around the issue.

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  • Small maximum number of connections on a Linux router

    - by Eugene
    I have a Linux box acting as a router with no iptables or other firewall and no networking applications running on it, just pure router. I've put it in a test environment that generates many TCP connections, each having unique source and destination IP, and those connections go through this router. I'm observing that number of connections successfully created rise to approximately 500 and then no more connections can be created for several minutes, then another 100 connections can be created and there is another pause, and so on. If 10 connections for each source-destination pair are created, then maximum numbers go about 10 times up, so the problem is probably with many connections from different IPs. As traffic is simply routed, it doesn't have to do with number of file descriptors, iptables connection tracking and other things often proposed to check in similar cases. The box has plenty of free RAM and CPU, both NICs are gigabit. The kernel is 2.6.32. I've already tried increasing net.core.*mem_max, net.core.netdev_max_backlog and txqueuelen on both NICs, with completely no effect. What else should I check ? Is there some rate-limit in the kernel itself ?

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  • Linux iptables / conntrack performance issue

    - by tim
    I have a test-setup in the lab with 4 machines: 2 old P4 machines (t1, t2) 1 Xeon 5420 DP 2.5 GHz 8 GB RAM (t3) Intel e1000 1 Xeon 5420 DP 2.5 GHz 8 GB RAM (t4) Intel e1000 to test linux firewall performance since we got bitten by a number of syn-flood attacks in the last months. All machines run Ubuntu 12.04 64bit. t1, t2, t3 are interconnected through an 1GB/s switch, t4 is connected to t3 via an extra interface. So t3 simulates the firewall, t4 is the target, t1,t2 play the attackers generating a packetstorm thorugh (192.168.4.199 is t4): hping3 -I eth1 --rand-source --syn --flood 192.168.4.199 -p 80 t4 drops all incoming packets to avoid confusion with gateways, performance issues of t4 etc. I watch the packet stats in iptraf. I have configured the firewall (t3) as follows: stock 3.2.0-31-generic #50-Ubuntu SMP kernel rhash_entries=33554432 as kernel parameter sysctl as follows: net.ipv4.ip_forward = 1 net.ipv4.route.gc_elasticity = 2 net.ipv4.route.gc_timeout = 1 net.ipv4.route.gc_interval = 5 net.ipv4.route.gc_min_interval_ms = 500 net.ipv4.route.gc_thresh = 2000000 net.ipv4.route.max_size = 20000000 (I have tweaked a lot to keep t3 running when t1+t2 are sending as many packets as possible). The result of this efforts are somewhat odd: t1+t2 manage to send each about 200k packets/s. t4 in the best case sees aroung 200k in total so half of the packets are lost. t3 is nearly unusable on console though packets are flowing through it (high numbers of soft-irqs) the route cache garbage collector is no way near to being predictable and in the default setting overwhelmed by very few packets/s (<50k packets/s) activating stateful iptables rules makes the packet rate arriving on t4 drop to around 100k packets/s, efectively losing more than 75% of the packets And this - here is my main concern - with two old P4 machines sending as many packets as they can - which means nearly everyone on the net should be capable of this. So here goes my question: Did I overlook some importand point in the config or in my test setup? Are there any alternatives for building firewall system especially on smp systems?

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  • What's throttling the database?

    - by Troels Arvin
    Hardware: Intel x86_64 with 192GB of RAM. OS: CentOS 5.4 x86_64. DBMS: DB2 v. 9.7.1 64 bit. During certain special workloads (e.g. parallel REORGs/RUNSTATs), I've seen the server transporting 450MB/s with 25000IO/s (yes, there is probably some storage system caching happening here) while all CPU cores were happily working in an even mix of usermode/wait. And disk benchmark tools can also bring some very satisfying bandwith and IO/s numbers to the table. On the other hand, we also have another scenario: A single rather complex query with at least one large table scan. db2's "list applications" reports that the query is Executing (not locked). IO: At most 10MB/s, 500 IO/s; CPU: two cores in 99.9% wait state, all other cores 100% idle. The tables which the query reads from have been altered to have LOCKSIZE=TABLE, so I would think that lock list work is zero. What's going on in such a situation? What tools/snapshots/... can I use to gain better insight in such a case?

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  • Windows 7 mouse multi selection on windows explorer with CTRL and point to select / single click to open

    - by bortao
    This is something that have annoyed me since i changed to Windows 7. I don't do double click for a long time now since windows introduced 1 click selection (Folder Options Click items as follows Single click to open an item). The problem is, when i click Control and hover over the items, they select/deselect automatically every small amount of mouse movement i make. What i want is to select/deselect the items only when i enter/exit them. So to deselect an item im hovering, i have to move the mouse out of it, and then back in. I'm using Intellimouse Explorer official drivers. (edit) Here's another related annoyance: When you are hovering something and move the mouse inside other item (Holding Ctrl) The new item may or may not be selected. If you continue moving the mouse it gets selected/deselected as you move. (more edit) I have found that the parameter HKCU\Control Panel\Mouse\MouseHoverHeight / MouseHoverWidth have some influence here. If it's set to 2, the item select/deselect really quickly as you move the mouse. When set to larger numbers, its slower. But setting to 20 or 200 don't seem to be much different.

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  • What is the fall off of subsecond throughput on Ethernet Network Interfaces

    - by Kyle Brandt
    On a network interface, speeds are given in term of data over time, in particular, they are bits per second. However, in the uber-fast world of computing -- a second is kind of a really long time. So for example, given a linear falloff. A 1 GBit per second interface would do 500MBit per half second, 250Mbit per quarter second etc. I imagine at certain units of time, this is no longer linear. Perhaps this is set by ethernet frequencies, system clock speeds, interrupt timers etc. I am sure this varies depending on the system -- but does anyone have more information or whitepapers on this? One of the main reasons I am curious is to understand output drops on interfaces. Even if the speed per second is much lower than the interface can handle -- perhaps there are spikes that cause drops for only small numbers of milliseconds. Perhaps various coalescing would hide this effect -- or perhaps increase it on the receiving interface? Do queues make a difference here? Example: So given if this is linear down to the MS we would have 1Mbit/MS, and if Wireshark isn't distorting what I see, should I see drops when I have a spike beyond 1Mbit?

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