Search Results

Search found 19055 results on 763 pages for 'high performance'.

Page 479/763 | < Previous Page | 475 476 477 478 479 480 481 482 483 484 485 486  | Next Page >

• Why do some machines respond with many RST packets instead of RST-ACK to refuse a connection?

  - by Michael J. Gray

  I have recently been trying to track down a problem with one of our systems and have noticed that it is simply not allowed to connect to a remote machine. However, the remote machine (not controlled by us) is responding to our request for a connection with many TCP RST packets on a different port (26469, 26497, 26498) than the one we originated on (53). It simply wouldn't let up at one point and flooded us with about 10 packets/second for an hour or two of only RST on those obscure high ports. Out of the thousands of nodes we're connecting to, this is the only one ever to show this behavior. What could possibly cause this? EDIT Below is a screenshot of Wireshark when it happened. I don't have the actual dump anymore and can't reproduce this specific scenario every time. Basically, we sent a SYN and immediately got RST on an odd port and so we respond with RST and just keep going back and forth.

  Read the article

• How to get the spec of a machine on Linux?

  - by machinePurchaser

  I am interested in getting the spec of a machine, because I am thinking getting a similar server. What I am mostly interested in knowing is the number of cores / CPUs / etc., the amount of memory, the speed of the CPUs, the CPU cache size, and any other detail which is important for performance. My question is two-fold: Which parameters should I be interested in other than the ones I specified above? Is there an easy way to read them off the machine in Linux? cat /proc/cpuinfo reveals a lot about the CPUs, for example... What about memory (would rather not rely on top), etc?

  Read the article

• What type of security problems are mitigated by this .NET architecture?

  - by Jonno

  Given the following physical layout for a .NET web application: DB (sql server, windows) - No public route (no table access, only stored procs) Web Service DAL (iis, windows) - No public route (can be accessed by web server via port 80 and 443) Web Server (iis, windows) - Public route (only via port 80 and 443) What type(s) / examples of attack could be used to compromise the public web server but would be blocked by the Web Service DAL? i.e. can you think of concrete attack types that the DAL stops? Please note, I am interested only in the security aspect, not scaling / fault tolerance / performance / etc. In my mind if the web server has been compromised using an attack over port 80/443, then the same attack would work over port 80/443 to the Web Service DAL box.

  Read the article

• nginx errors: upstream timed out (110: Connection timed out)

  - by Sparsh Gupta

  Hi, I have a nginx server with 5 backend servers. We serve around 400-500 requests/second. I have started getting a large number of Upstream Timed out errors (110: Connection timed out) Error string in error.log looks like 2011/01/10 21:59:46 [error] 1153#0: *1699246778 upstream timed out (110: Connection timed out) while reading response header from upstream, client: {IP}, server: {domain}, request: "GET {URL} HTTP/1.1", upstream: "http://{backend_server}:80/{url}", host: "{domain}", referrer: "{referrer}" Any suggestions how to debug such errors. I am unable to find a munin plugin to keep a check on number of upstream errors. Sometime the number of errors per day is way too high and somedays its a more decent 3 digit number. A munin graph would probably help us finding out any pattern or correlation with anything else How can we make the number of such error as ZERO

  Read the article

• smartOS HPC config suggestion

  - by Andrew B.

  I'm configuring a brand new HPC server and am interested in using SmartOS because of it's virtualization control and zfs features. Does this configuration make sense for a SmartOS HPC, or would you recommend an alternative? System Specs: 2x 8-core xeon 384 GB RAM 30 TB HDs with 2x512GB SSDs Uses: - zfs for serving data to different vms, and over the network; 1 SSD for L2ARC and 1 for ZIL - typically 1-2 ubuntu instances running R and custom C/C++ code My biggest concerns as a newbie to SmartOS and ZFS are: (1) will I get near-metal performance from ubuntu running on SmartOS if it is the only active vm? (2) how do I serve data from the global zfs pool to the containers and other network devices?

  Read the article

• gunzip unexpected end of file

  - by Mark J Seger

  I like to write high volume data directly to a zip file via perl. Works like a champ! However, on some rare occasions I've found that gunzip can't uncompress them declaring an unexpected end-of-file. The thing is I can uncompress it with a simple perl script, which probably misses the corrupted record(s) at the end. My question is, does anyone know of a way to use a standard utility to do the same thing? Maybe with a 'compress-as-much-as-you-can' switch? -mark

  Read the article

• Windows 8 Color Settings (Window Title)

  - by xixixao

  In Windows 7, the window title's color (by default black, to see the title in the title bar fire up Windows Media Player for example) is stored in [HKEY_CURRENT_USER\Control Panel\Desktop\Colors] TitleText value. This is not the case in Windows 8, since this value is only used when using high contrast theme. It looks like noone has come up with a way to change this color yet, so my question is, where to look? What tools can I use to see dependencies, what could be the way to find this value (I rightfully hope it's not a constant in code).

  Read the article

• SQL server availability issue: large query stops other connections from connecting

  - by Carlos

  I've got a high-spec (multicore, RAID) server running MS SQL 2008, with several databases on it. I have a low throughput process that periodically needs a small amount of information from one of the DBs, and the code seems to work fine. However, sometimes when one of my colleagues does a huge query against one of the other DBs, I see full CPU usage on the machine, and connections from my app time out. Why does this happen? I would have thought the many cores and harddisks would somehow (together with cleverly written DB server) be able to keep at least some of the resources free for other apps? I'm pretty sure he doesn't use multiple connections for his query. What can I do to prevent this?

  Read the article

• Is paravirtualization evil?

  - by Daniel

  I have an VMWare ESX Server v3.5 with a few virtualized Debian Lenny VMs (kernel 2.6.22 with vmi) running Apache Tomcat 5.5. I enabled paravirtualization, and Disk IO increased from about 240MB/s to 380MB/s, making me a happy admin. The problem now is that my apache tomcat becomes deadlocked during startup, running with 200% CPU (I have 2 CPUS assigned to the VM), and don't know how to get both: A stable system and a fast system. I somewhere heared that paravirtualization is legacy anyway and won't be available on newer ESX servers. Is there a replacement for this seemingly performance-improving option, or is it discontinued becauses it is just unstable? What is the state of paravirtualization? Should I ignore it completely? Thanks for all answers in advance.

  Read the article

• What's faster for web-server virtualization ? (virtualbox or KVM)

  - by marc

  I have question, does anyone try to set up a webserver (debian) using virtualbox (x64) ? Right now i have few servers in KVM (x64) but i think it work slowly... Can i get something more (faster, performance) using virtualbox (x64)? On my home installation it looks very fast. Should i move to vbox against kvm ? I'm looking for answer from someone who have in virtualbox (x64) real server (can be headless) (debian/ubuntu) not windows xp or other home using things ;) I also got xp, 2k3, ubuntu in virtualbox (x86) and for me looking faster than kvm(x64). But it's hard to say anything without real tests done by multiple users not just one.

  Read the article

• block access to certain website types

  - by frustrated teacher

  Need to block access to certain website types without listing each URL to block. Students at secondary school are going to porn sites. Need to be able to block all such access without having to list each possible site URL. Having the Content -- Ratings tab set to None for all categories on the ratings files listed on my computers does not prevent access. Unchecking users may access sites with no rating, even with the security settings set to High, still allows the porn sites to come up. If that is checked, then ONLY listed sites can open and students would not be able to do any research via google, for example. I would rather not have to continue checking each computer and blocking sites as they find them.

  Read the article

• How do you handle the task of changing the schema of a production MySQL database?

  - by Continuation

  One of the biggest complaints I have heard about MySQL is that it locks up a table if you try to change its schema like adding a column or adding an index. By "locking up the table" does it mean I can neither read nor write to the table? Sometimes for hours? That seems a pretty severe limitations. I was going to use MySQL for my new project but this gives me pause. Is there a workaround for this? How do you handle the task of changing the schema of your production MySQL database? By the way someone told me Postgresql doesn't have this problem. Is that true - I can both read and write to a Postgresql table while changing its schema? Is there any performance penalty incurred? Would love to hear your experiences.

  Read the article

• Access a windows dynamic hard drive through a virtual machine on ubuntu?

  - by Enigma

  I have a Windows 7 OS and am thinking about transitioning to a dual boot set up with Ubuntu 12.04. From what I recall, it is not possible to natively access Dynamic Windows Partitions in a Linux OS. My thought is that it might be possible to have a virtual machine (running windows) installed within Ubuntu access the physical dynamic drive. The problem comes to whether VMWare can access the physical disk "high enough" to be able to mount it within the windows virtual machine as a native device or if it gets passed through from the native Linux OS. This is really the only thing holding me back from switching to a dual-boot set up as the dynamic disk is made up of 4 or 5 hard drives and I would very much like access to the data on both OS's. Alternatively, is there another solution for combining multiple physical hard drives into one virtual hard drive that would be readable on both OS's?

  Read the article

• Create a dependent drop down list in a single cell in Excel

  - by Larry Anderson

  I am trying to create a dependent drop down list for a High School. The User will select cell A1, Click on Hallway 3(for example), then the user will click on cell A1 again and then select the Room #, 325 (for example). The final result should be that cell A1 shows 325. I can create the first drop down list, but the second part is where I am having great trouble. I am using Excel 2010. Any help would be appreciated. Thanks

  Read the article

• Configuring bridged network connection --- Windows 7 host, Ubuntu 10.04 guest --- VMWare Workstation 8

  - by H3br3wHamm3r81

  Here is my IPCONFIG /ALL from the host (Windows 7 64-bit): Here is my IFCONFIG from the guest (Ubuntu 10.04): To be honest, I don't have experience configuring a network between a host and a guest in VMWare (a virtual machine). I've searched high and low on the internet, but I haven't seen anything that can help. Perhaps I'm just not using the right keywords when I search. Nevertheless, does anyone here have any experience with establishing a network connection? Edit: One important note. I don't use DHCP to provide private addresses to the hosts on my LAN. I use "static" IP addresses on my internal network by configuring each IP address manually in the host's network configuration utility (I have TV's, XBOX 360, and a few PC's). I would like to configure the IP on the virtual machine guest manually as well. The reason is because my XBOX 360 only works properly using a static IP address. It will kick me off XBOX Live if it has one given by the router (via DHCP).

  Read the article

• Suggestions for someone wanting to become a Laptop Reseller

  - by Josh B.

  First of all, to give you a little background... I have had my Microsoft A+ for several years now. I used to run a small business repairing Xbox 360 consoles and I am currently a Network Engineer for a company in Ohio. I definitely know my way around a computer. I miss running a small business on the side and I'd like to get something going again. There is a really high demand in my area for Laptops and I was thinking about starting a small Laptop store out of my house. What is the best way to do this? I was assuming that the best way would be to buy barebones systems and build them yourself. If this is the best method, I would be very interested in any resources to get parts and such. Apparently Laptop parts aren't the easiest thing to come by (especially at a good price). Does anyone have any suggestions about how to get something like this going?

  Read the article

• How can I see if apache is overloaded and dropping or not accepting connections?

  - by cat pants

  Basically I just want to see if apache is handling a current level of high traffic or if I need to tune it to handle more connections. (I have found plenty of information on the actual tuning, so no help needed there) I know it has been dropping or not accepting connections earlier today, but not seeing anything in the error logs. Is the expected behavior to throw a 503 in the error log if apache cannot accept more connections? If so, what error logging level do I need in order to see these? What is the correct terminology: dropping connections or not accepting connections? MPM is prefork, OS is Linux, apache version is 2.2.15.

  Read the article

• How SSD's drives reduce their latency?

  - by tigrou

  First time i read some information about SSD's, i was surprised to learn they internally use NAND flash chips. This kind of memory is generally slow (low bandwidth) and have high latency while SSD's are just the opposite. But here is how it works : SSD drives increase their bandwidth by using several NAND flash chips in parallel. In other words, they do some data striping (aka RAID0) across several chips (done by the controller). What i don't understand is how SSD's drives managed to reduce latency? (or at least lot better than what a single NAND chip without any controller can do)

  Read the article

• better options for screen?

  - by lonestar21

  OK. So I love screen. It has saved my bacon a few times when machines crash or get disconnected from the network. However, there are enough reasons keep keep me from using screen for everything, which include: Pain in the butt scrolling. Why can't I just interact as though this is a normal bash shell? My keyboard shortcuts are gone. I have a number of things customized in my bash environment, is there a way to get them to work in screen as well? Are there any tools our tips that I can use to make my screen-using experience as high quality as my bash using experience?

  Read the article

• TCP 30 small packets per second flood connection with server

  - by Denis Ermolin

  I'm testing connection with flash client and cloud server(boost::asio for software) over TCP connection. My connection with server already is really poor - 120 ms ping in average. I found when i start to send packets with 2 bytes size (without tcp header) with speed 30 packets/s - ping grow to 170-200 average. I think that it's really bad and my bad connection and bad cloud provider is reason for this high ping without any load. What do you think? (I tested my software - it can compute about 50k small packets/s so software is not a problem). I measure my ping through flash client - send packet with timestamp and immediatly send from server to client.

  Read the article

• Upgrade no raid server to raid

  - by AZee

  I have just learned that our PDC has a single drive with 2 partitions. I also know that this drive has bad blocks as recorded in the event log. What I would like to do is to convert this to a RAID solution with a nice balance between economy and performance. I will admit that I have only configured servers with RAID from scratch, and have no experience upgrading an existing system into a RAID system. In fact, I'm not sure it is even possible. Since this is the PDC for 350+ workstations downtime is important. I'd like to hear from other System Administators how they would tackle this and their recommendations for all devices. At this time it seems to me that I can replace the existing drive and then restore from backup or install a controller, drives, configure the RAID an basically start from scratch. Thank you for taking your time. ~AZee

  Read the article

• How to find malicious IPs?

  - by alfish

  Cacti shows irregular and pretty steady high bandwidth to my server (40x the normal) so I guess the server is udnder some sort of DDoS attack. The incoming bandwidth has not paralyzed my server, but of course consuming the bandwidth and affects performance so I am keen to figure out the possible culprits IPs add them to my deny list or otherwise counter them. When I run: netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n I get a long list of IPs with up to 400 connections each. I checked the most numerous occurring IPs but they come from my CDN. So I am wondering what is the best way to help monitor the requests that each IP make in order to pinpoint the malicious ones. I am using Ubuntu server. Thanks

  Read the article

• Sending a large number of mails causing problems on CentOS 6 / Plesk 10

  - by papakost

  I have a VPS running CentOS 6. When the system tries to send daily newsletter, after some time (e.g. after sending about 2000 emails), I get error "Unable to send mail" and the system memory goes really high. Till this moment, the mails are delivered normally. The rest symptoms are: I cannot see anything on /var/log/maillog (File seems not to be written) All files on /var/spool/mail have 0 bytes size. From time to time on httpd log I get errors like: /usr/sbin/sendmail: error while loading shared libraries: libc.so.6: cannot open shared object file: Error 23 "Activate mail service on domain" setting in Plesk is deactivated. Any idea on what's going wrong here?

  Read the article

• Sudden slow read & write speed on all IO

  - by user23392

  I have a custom built rig that has 2 storage drives. for OS: Western Digital 1.0TB HARD DR 64MB for other stuff: Corsair Performance 3 128GB (SSD) [ expected read speed: 400 mb/s ] The system was incredibly fast for a couple of months, then one day i was playing a game then it started to get buggy (some sounds and objects disappearing), i stopped the game and the system seemed to be unstable so i had to shut it down, next morning i couldn't start it up, it was saying something about corrupt device. I formatted both disks and installed a fresh copy of windows, all i can say that since that day the system was never like before, it takes 10 minutes to boot up (the icons and desktop slowly appear). but once it's done the slowness isn't as noticeable. Here's my benchmark on the HDD ( read speed - write speed ): And the SSD: Anyone knows what could be the issue?

  Read the article

• Virtualbox, merging snapshots and base disk

  - by Henrik

  Hi, I have a virtual machine with about 30 snapshots in branches. The current development path is 22 snapshots plus the base disk. The amount of files is seemingly having an impact now on IO and the dev laptop I'm using (don't know if it is host disk performance issues with the 140GB total size over a lot of fragments, or just the fact that it is hitting sectors distributed across a lot of files). I would like to merge the current development branch of snapshots together with the base disk, but I am unsure if the following command would produce the correct outcome. I am not able to boot this disk after the procedure completes (5-6 hours). vboxmanage clonehd "C:\VPC-Storage\.VirtualBox\Machines\CRM\Snapshots\{245b27ac-e658-470a-b978-8e62137c33b1}.vhd" "E:\crm-20100624.vhd" --format VHD --type normal Could anyone confirm if this is the correct approach or not?

  Read the article

< Previous Page | 475 476 477 478 479 480 481 482 483 484 485 486  | Next Page >