Questions tagged [ionice]

25 questions
15
votes
2 answers

rsync ionice destination

To avoid rsync to starve the system and network we use ionice when starting rsync and set the --bwlimit parameter. For example: ionice -c2 -n7 rsync -aH --bwlimit=30000 /foo root@dest.com:/ This does indeed help to ensure the source server remains…
Jason Smith
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9
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1 answer

Use cases for having different process priority for CPU and IO?

Linux processes can have different CPU and IO priority (nice and ionice). Why is there a need to have different CPU and IO priority? Is there any real world usage for having them different? What real world use cases have you found that need…
Eduardo
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8
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1 answer

rrdgraph generation fails on high IO load

We have a 4 core CPU production system which does a lot of cronjobs , having constant proc queue and an usual load of ~1.5. During night time we do some IO intensive stuff with postgres. We generate a graph showing the load/memory usage…
Dennis Nolte
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8
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3 answers

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

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…
David Eyk
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7
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2 answers

nice, ionice are not enough

I have a script that starts big, CPU and memory consuming tree of processes. There is Python and executables down there, but everything starts with single bash script and python subprocesses. During the execution, rest of system is completely…
MateuszL
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7
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1 answer

Making the kernel aware of device colocation

I have a server with a big hardware RAID6 array that's been configured with two volumes, presented by Linux as sda and sdb (yeah, I know, but it's a rented colo that came configured this way, and sadly I have to live with it). I have an…
Flup
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7
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2 answers

Can I throttle tar without ionice?

My tar command tar --remove-files -cvif 2011-08-02_14-05-09.tar 2011-08-02_14-05-09 Writes 80MB/s. That's beyond the capacity we can spare because MySQL starts queuing up writes and eventually we get monitoring alerts cause systems won't wait…
kvz
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7
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2 answers

How to set i/o priority for nfs client processes?

The configuration is: A linux server and a nas box (netgear) acting as nfs server. It is easy for a single process on the linux server to use all i/o bandwidth by simply copying a file from the nfs share to the nfs share. The i/o channel is jammed…
Moritz Both
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6
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1 answer

How long is the "defined grace period" for the idle scheduling class of the CFQ io scheduler?

The ionice man page says A program running with idle io priority will only get disk time when no other program has asked for disk io for a defined grace period. Where is this "grace period" defined? Is it visable/tunable (perhaps via /sys)?
jhfrontz
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5
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1 answer

ionice vs. Software-RAID

Does ionice work in Software-RAID environments? I cannot set the CFQ scheduler for the md devices, because there is no file /sys/block/md0/queue/scheduler . It seems that the scheduler settings for the underlying disks are not propagated to the raid…
der_flo
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5
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2 answers

ionice idle is ignored

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 ionice -c 3 du If I check both process in iotop I see…
5
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1 answer

How do I test the effect of ionice (against a device using the cfq scheduler)?

I'm trying to construct an experiment to measure the effect of ionice. What I'd like to do is to (per another answer on serverfault) cause frequent enough I/O that a sufficiently "niced" process is starved of any I/O. Based on another answer on…
jhfrontz
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3
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3 answers

Is it possible to assign a nice and ionice priority to all scripts executed by cron daemon?

To be a bit more concrete: I have a Debian Squeeze Linux machine with a web application that should become available all over the planet. Until now I had a bunch of resource consuming cronjobs each night (in Europe) without much impact on regional…
Miguel ZP
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3
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2 answers

ionice without effect

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…
tim
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2
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rsync: Maximum nice to keep system responsive

Unfortunately a background rsync reduces the responsiveness of a server. I search a way to have maximum niceness for this background task, to keep the server respond fast. My current wrapper commands are this: nice -n19 ionice -c3 nocache Source:…
guettli
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