Search Results

Search found 4688 results on 188 pages for 'io redirection'.

Page 28/188 | < Previous Page | 24 25 26 27 28 29 30 31 32 33 34 35  | Next Page >

• How to identify heavy write to disk?

  - by Darth

  I have this problem with server running CakePHP application. The server is insanely slow, I first thought that it's application problem, but then I found constant 5-6MB/s write to disk. What is the easiest way to find cause of such a heavy write? The server is running Gentoo.

  Read the article

• I/O intensive MySql server on Amazon AWS

  - by rhossi

  We recently moved from a traditional Data Center to cloud computing on AWS. We are developing a product in partnership with another company, and we need to create a database server for the product we'll release. I have been using Amazon Web Services for the past 3 years, but this is the first time I received a spec with this very specific hardware configuration. I know there are trade-offs and that real hardware will always be faster than virtual machines, and knowing that fact forehand, what would you recommend? 1) Amazon EC2? 2) Amazon RDS? 3) Something else? 4) Forget it baby, stick to the real hardware Here is the hardware requirements This server will be focused on I/O and MySQL for the statistics, memory size and disk space for the images hosting. Server 1 I/O The very main part on this server will be I/O processing, FusionIO cards have proven themselves extremely efficient, this is currently the best you can have in this domain. o Fusion ioDrive2 MLC 365GB (http://www.fusionio.com/load/-media-/1m66wu/docsLibrary/FIO_ioDrive2_Datasheet.pdf) CPU MySQL will use less CPU cores than Apache but it will use them very hard, the E7 family has 30M Cache L3 wichi provide boost performance : o 1x Intel E7-2870 will be ok. Storage SAS will be good enough in terms of performance, especially considering the space required. o RAID 10 of 4 x SAS 10k or 15k for a total available space of 512 GB. Memory o 64 GB minimum is required on this server considering the size of the statistics database. Warning: the statistics database will grow quickly, if possible consider starting with 128 GB directly, it will help. This server will be focused on I/O and MySQL for the statistics, memory size and disk space for the images hosting. Server 2 I/O The very main part on this server will be I/O processing, FusionIO cards have proven themselves extremely efficient, this is currently the best you can have in this domain. o Fusion ioDrive2 MLC 365GB (http://www.fusionio.com/load/-media-/1m66wu/docsLibrary/FIO_ioDrive2_Datasheet.pdf) CPU MySQL will use less CPU cores than Apache but it will use them very hard, the E7 family has 30M Cache L3 wichi provide boost performance : o 1x Intel E7-2870 will be ok. Storage SAS will be good enough in terms of performance, especially considering the space required. o RAID 10 of 4 x SAS 10k or 15k for a total available space of 512 GB. Memory o 64 GB minimum is required on this server considering the size of the statistics database. Warning: the statistics database will grow quickly, if possible consider starting with 128 GB directly, it will help. Thanks in advance. Best,

  Read the article

• I/O APIC on Virtualbox

  - by RidDeBakTiYar

  I'm trying to use the PIT to do APIC timer calibration, and I want to use the PIT through I/O APIC instead of PIC. On Bochs I get interrupts from the PIT at the asked frequency from the I/O APIC, while on Virtualbox I can't receive a single interrupt. It must be an I/O APIC configuration problem because as I unmask the first PIC entry, the IRQ fires. However that's not what I want. Can you imagine any possible condition that wouldn't make Virtualbox fire the IRQ? I'm not assuming single I/O APIC configuration (even though Virtualbox has only 1). I'm not assuming identity mappings between ISA IRQs and I/O APIC GSIs (using ACPI MADT table to get I/O APIC base address and Int override). I'm setting the Trigger Mode and Polarity bits correctly (on Virtualbox they are set as '00 - default' which means edge high right?). I'm putting the BSP APIC ID into the Destination field (using Physical destination) and vector 0x20. Being the BSP APIC ID 0 on Virtualbox, it ends up with 0x0000000000000020 written to the IOREDTBL. And, just in case I'm getting the wrong values from the Interrupt Override descriptor, I'm setting this value to all the IOREDTBL entries (I know this is very very bad, and it wont be kept as I understand what's going on). The only thing I didn't check out is Local APIC configuration. Actually I'm not writing any value to the BSP LAPIC. Just reading the APIC ID and using it to boot APs through IPIs. And obviously I'm setting bit 11 in the IA32_APIC_BASE MSR to enable the LAPIC. Any ideas? Thanks in advance.

  Read the article

• Will adding a SSD cache device to my ZFS storage improve performance?

  - by Sysadminicus

  The server has 4GB of RAM and my zpool is made up of 15.5k SAS drives arranged like this: NAME STATE READ WRITE CKSUM tank ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 c0t2d0 ONLINE 0 0 0 c0t3d0 ONLINE 0 0 0 c0t4d0 ONLINE 0 0 0 c0t5d0 ONLINE 0 0 0 c0t6d0 ONLINE 0 0 0 c0t7d0 ONLINE 0 0 0 c0t8d0 ONLINE 0 0 0 raidz1-1 ONLINE 0 0 0 c0t10d0 ONLINE 0 0 0 c0t11d0 ONLINE 0 0 0 c0t12d0 ONLINE 0 0 0 c0t13d0 ONLINE 0 0 0 c0t14d0 ONLINE 0 0 0 spares c0t9d0 AVAIL c0t1d0 AVAIL The primary use is as an NFS store for a couple VMWare ESXi servers. I can't do any "true" benchmarks because this is a production system (no budget for test systems), but using dd and bonnie++ I can't get more than ~40-50MB/s writes and ~70-90MB/s reads. It seems I should be able to do much better, but I'm not sure where to optimize. Based on what I've read, I think dropping in a OCZ Vertex 2 Pro SSD as my L2ARC is going to be the best bang-for-the-buck to improve througput. Is there something else I should be looking into to help performance? If not... How do I know how big a cache device I need? Am I safe with only a single SSD as my cache device?

  Read the article

• Need data on disk drive management by OS: getting base I/O unit size, "sync" option, Direct Memory A

  - by Richard T

  Hello All, I want to ensure I have done all I can to configure a system's disks for serious database use. The three areas I know of (any others?) to be concerned about are: I/O size: the database engine and disk's native size should either match, or the database's native I/O size should be a multiple of the disk's native I/O size. Disks that are capable of Direct Memory Access (eg. IDE) should be configured for it. When a disk says it has written data persistently, it must be so! No keeping it in cache and lying about it. I have been looking for information on how to ensure these are so for CENTOS and Ubuntu, but can't seem to find anything at all! I want to be able to check these things and change them if needed. Any and all input appreciated.

  Read the article

• RAID10 without write-back cache = horrible write performance?

  - by Harry Mexican

  I have just provisioned a dedicated server on singlehop. I'm running it through some tests to know what to expect performance-wise. On the I/O side (with 4 1TB disks in RAID 10) I get: write-cache disabled 200 MB/s read throughput 30 MB/s write throughput I thought that was really low compared to my desktop HD which gets 150-150 or so. So I had a chat with them and they suggested enabling the write cache. New results: write-cache enabled 280 MB/s read 260 MB/s write which is great and all but means I'd have to add a BBU for an additional monthly cost. Is it normal for the write throughput to be 1/4 of a regular drive on RAID10, if you don't have write cache? It almost feels like its intentionally bad to force you to pony up for the BBU. I'd be happy with normal non-raid performance of 150/150.

  Read the article

• Try to delete files used by IIS

  - by Cédric Boivin

  I got a service coded in c# whoes deleted somes web site files hosted on iis, before an update. But sometime when i delete the files, they stay there. If I try to delete them manually, via explorer, the file are not deletable, because they are in state "Delete pending". There is the way my service try to delete the file try { // Enlève tout les attributs sur le fichiers afin de s'assurer que le fichier n'est pas en lecture seul File.SetAttributes(file, FileAttributes.Normal); // Supprime le fichier File.Delete(file); } It's there a way to avoid this state ? What can i do to force the delete by c# code? Could i release all process to the file by c# code ? The environnement is IIS 7.5 Windows 2008-r2 .net 4.0 Thanks

  Read the article

• Windows Disk I/O Analysis

  - by Jonathon

  It appears that we are having a problem with the disk i/o speed on our Windows 2003 Enterprise Edition server (64-bit). As we were initializing a database that created two 1G tablespaces on 3 different machines, it became obvious that the two smaller machines (each 32-bit Windows 2003 Standard Edition with less RAM) killed the larger machine when creating the files. The larger machine took 10x as long to create the tablespaces than did the other machines. Now, I am left wondering how that could be. What programs or scripts would you guys recommend for tracking down the I/O problem? I think the issue may be with the controller card (all boxes are hardware RAID 10, but have different controller cards), but I would like to check the actual disk I/O speed as well, so I have some hard numbers to work with. Any help would be appreciated.

  Read the article

• Determining Performance Limits

  - by JeffV

  I have a number of windows processes that pass messages between them hat a high rate using tcp to local host. Aside from testing on actual hardware how can I assess what my hardware limit will be. These applications are not doing CPU intensive work, mostly decomposing and combining messages, scanning over them for special flag in the data etc.. The message size is typically 3k and the rate is typically ~10k messages per second. ~30MB per second between processing stages. There may be 10 or more stages depending. For this type of application, what should I look to for assessing performance? What do I look for in a server performance wise? I am currently running an XEON L5408 with 32 GB ram. But I am assuming cache is more important than actual ram size as I am barely touching the ram.

  Read the article

• How to increase the disk cache of Windows 7

  - by Mark Christiaens

  Under Windows 7 (64 bit), I'm reading through 9000 moderately sized files. In total, there is more than 200 MB of data. Using Java (JDK 1.6.21) I'm iterating over the files. The first 1400 or so go at full speed but then speed drops off to 4ms per file. It turns out that the main cost is incurred simply by opening the files. I'm opening the files using new FileInputStream (and of course closing them in time to avoid file leaks). After some investigating, I see that Windows' disk cache is using only 100 MB or so of RAM although I have 8 GiB available. I've tried increasing the cache size using the CacheSet tool but any values I provide are considered out of range. I've also tried enabling the LargeSystemCache registry key but (after rebooting) the CacheSet tool still indicates I'm using 100 MB of cache (and doesn't increase during the test run). Does anybody have any suggestions to "encourage" Windows 7 to cache my 9000 files?

  Read the article

• I/O Reads and Writes per process Unix/SunOS?

  - by Alex

  Can prstat or something similar tell me how many reads/writes a process is doing similar to how Task Manager on Windows can show I/O Reads, I/O Writes and many other I/O columns per process? I'm using SunOS 5.10, but feel free to post other Unix flavours too.

  Read the article

• replacement drive cage for power edge R710

  - by bumble_bee_tuna

  Hi I'm performance tuning a DB server its a Dell R710 there is a very significant I/O bottleneck. Unfortunately the server was purchased with the 6 x 3.5 inch sata configuration which doesn't give me the leeway I need to address the issue. Before going to DAS does anyone know if it is possible to purchase a replacement front drive enclosure ? I know the server is configurable with something like 12 or 16 2.5 inch drives and it appears to be modular ? I tired contacting dell but the offshore parts department reps are not very bright lol. Thanks.

  Read the article

• poor performance when deleteing many files

  - by choppy

  I've got two machines: The first is IBM Blade with 24 cores 96GB RAM and single local hard drive with 278GB divided to 4 partitions: 1. c: - 40GB; 3GB free 2. d: - 40GB; 37GB free 3. e: - 198322GB; 198.1 free 4. 100MB (EFI system Partition) Formatted with GPT The other is pizza server with 4 cores 8GB RAM and single local hard drive with 273GB divided to 3 partitions: 1. c: - 136.81; 20GB free 2. d: - 88.74GB; 87.91 free 3. e: - 47.85GB; 46.91 free Formatted with MBR I have two scripts, the first creates 20,000 files in one directory, each file size is 192KB, the second delete the folder (recursive) and prints how much time it toke to delete all files. The problem is on the first server (blade) it takes about 2 minutes to delete all 20,000 files while on the second (pizza) it takes about 4 seconds!? Both servers have clean windows server 2008R2 with no special application running on background. Any ideas what is going on?

  Read the article

• Is Joerg Schilling's "sdd" a full replacement for "dd"

  - by fishtoprecords

  I'm trying to use 'sdd' on my Debian system, and can't get one set of options to work. They do work in 'dd' so I am wondering if I am specifying them incorrectly, or if sdd didn't implement them, or something else. What I want to do is sdd if=/dev/hdh1 of=/bay5/imagebay1 bs=4096 conv=sync,noerror if I leave out the "conv=..." option, it works, or at least starts copying data. sdd if=/dev/hdh1 of=/bay5/imagebay1 bs=4096 Can you shed a bit of light?

  Read the article

• linux: accessing thousands of files in hash of directories

  - by 130490868091234

  I would like to know what is the most efficient way of concurrently accessing thousands of files of a similar size in a modern Linux cluster of computers. I am carrying an indexing operation in each of these files, so the 4 index files, about 5-10x smaller than the data file, are produced next to the file to index. Right now I am using a hierarchy of directories from ./00/00/00 to ./99/99/99 and I place 1 file at the end of each directory, like ./00/00/00/file000000.ext to ./00/00/00/file999999.ext. It seems to work better than having thousands of files in the same directory but I would like to know if there is a better way of laying out the files to improve access.

  Read the article

• Linux Read-Ahead Downsides

  - by JPerkSter

  Hi Everyone, Hope all is well. I have a question regarding read-ahead caching. Are there any downsides to raising the size of the read-ahead cache? On our farm, we're currently running at 256, and upon raising that higher, we are seeing significant throughput gains.   [root@server~]# hdparm -tT /dev/sda /dev/sda: Timing cached reads: 7352 MB in 2.00 seconds = 3677.62 MB/sec 3 Timing buffered disk reads: 244 MB in 3.10 seconds = 78.68 MB/sec [root@server ~]# blockdev --setra 10240 /dev/sda [root@server ~]# hdparm -tT /dev/sda /dev/sda: Timing cached reads: 11452 MB in 2.00 seconds = 5728.52 MB/sec Timing buffered disk reads: 422 MB in 3.17 seconds = 133.04 MB/sec We are running on 2.6. Thanks!

  Read the article

• Hiding "Syntax OK" from apache2ctl output

  - by Oscar Barrett

  I am checking whether a particular apache module is installed using apache2ctl -M. When listing the modules, apache runs a syntax check on the configuration files which prints out "Syntax OK" if everything is fine. However, this message doesn't seem to be coming from STDOUT or STDERR as it shows even if all output is redirected to /dev/null. i.e. $ sudo apache2ctl -M Loaded Modules: core_module (static) log_config_module (static) ... Syntax OK $ sudo apache2ctl -M >/dev/null Syntax OK How is this being outputted, and is it possible to hide?

  Read the article

• How can I set deadline as the I/O scheduler for USB Flash devices by using udev rules?

  - by ????

  I have set CFQ as the default I/O scheduler. I often get bad performance when I write data into a Flash device. This is resolved if I use deadline as the I/O scheduler for USB Flash devices. I can't always change the scheduler manually, right? I think writing udev rules is a good idea. Can someone please write rules for me? I want: When I plug in a USB device, detect the type of the device. If it is a portable USB hard disk, do nothing (I think if a device has more than one partitions, it always a portable hard disk. If it is a USB Flash device, set deadline as it's scheduler.

  Read the article

• How do I know if my disks are being hit with too many I/O reads or writes or both?

  - by Mark F

  I know a bit about disk I/O and bottlenecks relating to this especially when relating to databases. How do I really know what the max I/O numbers will be for my disks? What metric might be available to me for working out roughly (but needs to be a good approximation) of how much capacity (if you will) have I got left available in I/O. I've seen it before where things are bubbling along nicely and then all of a sudden, everything screams to a halt, and it ends up being an I/O bound problem. Is there a better way to predict when I/O is reaching its limits? This article was interesting but not giving the answer I desire. So, is my best bet surrounding just looking at 'CPU I/O WAIT'? There must be a more reactive method than this.

  Read the article

• How to accelerate and notice failure of potentially faulty disks

  - by rainier

  Hey, I got a bunch of 'used' servers, whose disks should have been checked, but they have been shipped around the county in crate which can't help. I just had one disk go bad (despite being mirrored, currently trying to get more details). The server was fine for about a week before everything ground to a halt this afternoon. Is there any way 'accelerate' the failure of faulty disks, with the goal of bringing the disk to failure before we launch production services? Would doing lots of I/O with 'dd' or 'iozone' be a good way to test these potentially faulty disks? Any other tests/tools that would help recognized failures before they happen?

  Read the article

• performance monitoring

  - by Sunny

  I want to monitor CPU usage, disk read/write usage for a particular process, say ./myprocess. To monitor CPU top command seems to be a nice option and for read and write iotop seems to be a handy one. For example to monitor read/write for every second i use the command iotop -tbod1 | grep "myprocess". My difficulty is I just want only three variables to store, namely read/sec, write/sec, cpu usage/sec. Could you help me with a script that combines the outputs the above said three variables from top and iotop to be stored into a log file? Thanks!

  Read the article

• Full list of top-like tool family for perfomance monitoring in linux: iftop iotop htop atop more? [closed]

  - by Yauhen Yakimovich

  Top-like utilities are extremely handful in my work and I want to make sure I am not missing any of them. Please extend the following list of performance monitoring (top-like) family of linux tools: top - original tool htop - adds support to multicore/cpu iotop - input/output monitoring iftop - network monitoring atop - merges previous elements into a single overview slabtop – displays a listing of the top caches ? The only criteria - maturity and similarity in function/style.

  Read the article

• How to increase the disk cache of Windows 7

  - by Mark Christiaens

  Under Windows 7 (64 bit), I'm reading through 9000 moderately sized files. In total, there is more than 200 MB of data. Using Java (JDK 1.6.21) I'm iterating over the files. The first 1400 or so go at full speed but then speed drops off to 4ms per file. It turns out that the main cost is incurred simply by opening the files. I'm opening the files using new FileInputStream (and of course closing them in time to avoid file leaks). After some investigating, I see that Windows' disk cache is using only 100 MB or so of RAM although I have 8 GiB available. I've tried increasing the cache size using the CacheSet tool but any values I provide are considered out of range. I've also tried enabling the LargeSystemCache registry key but (after rebooting) the CacheSet tool still indicates I'm using 100 MB of cache (and doesn't increase during the test run). Does anybody have any suggestions to "encourage" Windows 7 to cache my 9000 files?

  Read the article

• Fastest security check of file tree on NFS

  - by fungs

  I am currently experiencing very bad performance using the following on an NFS network folder: time find . | while read f; do test -L "$f" && f=$(readlink -m $f); grp="$(stat -c %G $f)"; perm="$(stat -c %A $f)"; done Question 1) Within the loop permissions are checked using the variables grp and perm. Is there a way to lower the amount of disc I/O for these kind of checks over the network (e.g. read all meta data at once using find)? Question 2) It seems like the NFS isn't tuned very well, the same operation on a similar network link via SSHFS take only one third of the time. All parameters are auto-negotiated. Any suggestions?

  Read the article

• random hard disk errors

  - by AugB

  For the past 2 years or so (4 year old custom build) I've been getting random moments where everything stops responding (or takes a very long time to respond) followed by I/O and hdd not detected errors on restart. To fix it, all I usually need to do is unplug my SATA cables from the hdd and mobo and plug them back in again and the problem disappears, at least for a little while (it ranges anywhere from a day to a few months time). Sometimes even a startup repair does the job. I've done multiple reformats and have also ran chkdsk more times than I can remember and both do not seem to help in the long run. Both the drives seem to be exhibiting the same problem. Have both my hdds been "dying" for the past couple of years, even though they are fully functional besides these occasional hiccups? Does the issue lie elsewhere? All feedback is appreciated. System specs: Biostar Tpower i45 mobo 2x WD Caviar 640GB hdds Zalman 750w psu Radeon 5870 gpu 2x2gb Gskill DDR2 ram Win7 64

  Read the article

< Previous Page | 24 25 26 27 28 29 30 31 32 33 34 35  | Next Page >