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Search found 10 results on 1 pages for 'ionice'.

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• ionice idle is ignored

  - by Ferran Basora

  I have been testing the ionice command for a while and the idle (3) mode seems to be ignored in most cases. My test is to run both command at the same time: du <big folder> ionice -c 3 du <another big folder> If I check both process in iotop I see no difference in the percentage of io utilization for each process. To provide more information about the CFQ scheduler I'm using a 3.5.0 linux kernel. I started doing this test because I'm experimenting a system lag each time a daily cron job updatedb.mlocate is executed in my Ubuntu 12.10 machine. If you check the /etc/cron.daily/mlocate file you realize that the command is executed like: /usr/bin/ionice -c3 /usr/bin/updatedb.mlocate Also, the funny thing is that whenever my system for some reason starts using swap memory, the updatedb.mlocate io process is been scheduled faster than kswapd0 process, and then my system gets stuck. Some suggestion? References: http://ubuntuforums.org/showthread.php?t=1243951&page=2 https://bugs.launchpad.net/ubuntu/+source/findutils/+bug/332790

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• ionice without effect

  - by tim

  System is Ubuntu 10 LTS 64bit (2.6.35.31), I'm running on xen 4.0, no services active, cron stopped, scheduler is cfq for the disk /usr is mounted from: time find /usr -exec stat {} \; > /dev/null 2>&1 & giving real 0m35.760s user 0m0.270s sys 0m3.910s and time ionice -c3 find /usr -exec stat {} \; > /dev/null 2>&1 & giving real 0m36.110s user 0m0.310s sys 0m4.100s which is exactly as expected, now I run both at the same time: time find /usr -exec stat {} \; > /dev/null 2>&1 & time ionice -c3 find /usr -exec stat {} \; > /dev/null 2>&1 & where to my believe the ioniced version should be much slower while the straight version should be as fast as if running alone. but: straight: real 1m10.430s user 0m0.320s sys 0m3.940s ioniced: real 1m10.230s user 0m0.250s sys 0m4.020s which implies that ionice did not work at all. Any hints?

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• How to have a soft-real-time process in presense of heavily swapping IO-intensive background load?

  - by Vi

  schedtool: PID 32301: PRIO 4, POLICY R: SCHED_RR , NICE -20, AFFINITY 0xf ionice: realtime: prio 4 But the music is stumbling anyway. Background load is low prio (SCHED_IDLEPRIO, idle ionice), but uses a lot of memory (more than is physically available) and does a lot of IO and calculations. Latencytop shows about 1500ms for: Following symlink Writing buffer to disk (sync) Page fault Writing a page to disk both for the bg load and for unrelated processes. Load average is 10 and counting. Why cannot it allocate, for example, 200MHZ of one of the cores and 32M of memory and not less than once per second opportunity for IO for mplayer to make it happy while continuing calculations on the background? Or: why it cannot leave background task and swap loving each other but keeping the rest of the system as if there were no background load? How to have RT processes AND heavy bg load simultaneously (without of virtual machines)?

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• How to keep subtree removal (`rm -rf`) from starving other processes for Disk I/O?

  - by David Eyk

  We have a very large (multi-GB) Nginx cache directory for a busy site, which we occasionally need to clear all at once. I've solved this in the past by moving the cache folder to a new path, making a new cache folder at the old path, and then rm -rfing the old cache folder. Lately, however, when I need to clear the cache on a busy morning, the I/O from rm -rf is starving my server processes of disk access, as both Nginx and the server it fronts for are read-intensive. I can watch the load average climb while the CPUs sit idle and rm -rf takes 98-99% of Disk IO in iotop. I've tried ionice -c 3 when invoking rm, but it seems to have no appreciable effect on the observed behavior. Is there any way to tame rm -rf to share the disk more? Do I need to use a different technique that will take its cues from ionice? Update: The filesystem in question is an AWS EC2 instance store (the primary disk is EBS). The /etc/fstab entry looks like this: /dev/xvdb /mnt auto defaults,nobootwait,comment=cloudconfig 0 2

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• Renicing complex multithreaded applications in Linux

  - by Vi

  Applications (especially big Java and C++ ones) often shows up as multiple lines in htop, each have separate PID and separate nice level. Also application can spawn a lot of child processes (like as in aptitude update), so I need to affect both parent one (to make new children have new priority) and child ones (to bring the effect immediately, not after the child terminates) How can I apply "renice" or "ionice" or "schedtool" to already launched big application?

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• How can I run a job when the server load is low?

  - by jberryman

  I have a command that runs a disk snapshot (on EC2, freezing an XFS disk and running an EBS snapshot command), which is set to run on a regular schedule as a cron job. Ideally I would like to be able to have the command delayed for a period of time if the disk is being used heavily at the moment the task is scheduled to run. I'm afraid that using nice/ionice might not have the proper effect, as I would like the script to run with high priority while it is running (i.e. wait for a good time, then finish fast). Thanks.

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• Problems with the backup

  - by marcodv

  I did a script which run around 4 o'clock in the morning, for backup all the mysql databases and the config file for 250 linux vm. The problem is that it tooks ages for complete and more than 50% of these vm, need more than 8 hours for complete. More or less all the vm had the same configuration,I mean Same amount of ram same amount of disk space same number of cpu Debian 6.0.5 I am saving these backup on amazon s3, because is the cheapest solutions that I've found. Now my questions is: Has anyone some solutions or suggestions about that? On one blog I've read that probably the ionice and nice combination could be good work around about that. any thought?

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• Nightly backups (and maybe other tasks) causing server alerts

  - by J. Pablo Fernández

  I have two independent alert notification systems for my servers. The server is a virtual machine on Linode and one of the alerts comes from Linode. The other monitoring system we use is New Relic. They are both watching out for IO utilization. Every night I get alerts from both of them as the server is using too much IO. I run quite a few tasks in the middle of the night but the one I confirmed that can cause IO-warnings is running the backups. The backup is done by s3cmd sync. I tried ionice but it still generates the warnings. Getting warnings every night reduces the efficacy of warnings when they happen for real. For Linode I could raise the level at which a warning is issued, but it might mean making the whole thing useless as the level is too high. What would be the proper solution for this?

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• Windows Server 2008 R2 grinds to a screeching halt during file copy operations

  - by skolima

  When my Windows Server 2008 R2 machine is performing any large disk operations (copying 10GB files from one drive to another, copying similar file over network, merging HyperV snapshots, compressing large files), performance of the whole machine slows down terribly, everything becomes unresponsive. This is noticeable in any situation when the disk access is large enough not to fit in the cache. Are there any settings available for tuning this behaviour? I can accept slower file transfer if this would give me more responsiveness. System details: Dell Optiflex 960, Core 2 Quad Q9650, 8GB RAM, 2 SATA drives - 320GB (ST3320418AS) and 1TB (ST31000528AS), NCQ active on both, Intel 82564LM-3 Gigabit Ethernet, ATI HD 3450 graphics, Intel ICH10 bridge. We have multiple machines like this, every one is exhibiting the same behaviour. I though this was overkill for a workstation, apparently I was mistaken. Update: I guess I shouldn't have mentioned the HyperV at all. The above configuration is a standard workstation setup at the company I work for, this is not a server of any kind. I have at most 3 virtual machines working, and usually I'm the only person accessing them. Never the less, the slowdown occurs even when no VMs are running. On a Linux machine I'd simply ionice the copy process and I could forget about it, is there any way to manage IO priorities on Windows?

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• How can I limit the cache used by copying so there is still memory available for other cache?

  - by Peter

  Basic situation: I am copying some NTFS disks in openSuSE. Each one is 2TB. When I do this, the system runs slow. My guesses: I believe it is likely due to caching. Linux decides to discard useful cache (eg. kde4 bloat, virtual machine disks, LibreOffice binaries, Thunderbird binaries, etc.) and instead fill all available memory (24 GB total) with stuff from the copying disks, which will be read only once, then written and never used again. So then any time I use these apps (or kde4), the disk needs to be read again, and reading the bloat off the disk again makes things freeze/hiccup. Due to the cache being gone and the fact that these bloated applications need lots of cache, this makes the system horribly slow. Since it is USB,the disk and disk controller are not the bottleneck, so using ionice does not make it faster. I believe it is the cache rather than just the motherboard going too slow, because if I stop everything copying, it still runs choppy for a while until it recaches everything. And if I restart the copying, it takes a minute before it is choppy again. But also, I can limit it to around 40 MB/s, and it runs faster again (not because it has the right things cached, but because the motherboard busses have lots of extra bandwidth for the system disks). I can fully accept a performance loss from my motherboard's IO capability being completely consumed (which is 100% used, meaning 0% wasted power which makes me happy), but I can't accept that this caching mechanism performs so terribly in this specific use case. # free total used free shared buffers cached Mem: 24731556 24531876 199680 0 8834056 12998916 -/+ buffers/cache: 2698904 22032652 Swap: 4194300 24764 4169536 I also tried the same thing on Ubuntu, which causes a total system hang instead. ;) And to clarify, I am not asking how to leave memory free for the "system", but for "cache". I know that cache memory is automatically given back to the system when needed, but my problem is that it is not reserved for caching of specific things. Question: Is there some way to tell these copy operations to limit memory usage so some important things remain cached, and therefore any slowdowns are a result of normal disk usage and not rereading the same commonly used files? For example, is there a setting of max memory per process/user/file system allowed to be used as cache/buffers?

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