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Questions tagged [iostat]

90 questions
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Do we need to perform disk checking periodically on Linux

Do we need to perform periodic disk checking,for bad blocks and bad sectors?. Our servers havent been restarted for last 4 months,also no disk checking have been performed on any disks. Can that can cause any problem in the future or will it…
Kevin Parker
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tracking down what files are causing io activity in iostat

Using iostat -Nkx 1 I can see that I am getting regular IO on a volume group. What I'm trying to do is find a way to link that IO to a file/pipe/whatever to see what process is creating this IO and what destination it's hitting. Has anyone come…
Khushil
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very specific iostat output needed in realtime

Is there anyway to get the output of iostat -m and add only the column await from the extended output in realtime? I know this question sounds nutso but I need to be able to get all those column in realtime without outputing to a file or running…
egorgry
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RAID iostat showing 0.00 for wait's and %util

I have a EC2 server running ubuntu 11.10 with 6 raid devices, 5 with 8 EBS drives each as part of a RAID 10 setup, the other one with 4 EBS drives as part of a RAID 0 setup. I am finding that even though each of the individual EBS drive devices are…
Bryce Ewing
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high cancelled_write_bytes

On a MySQL server running on AWS EC2 with an EBS volume iostat returns the following avg-cpu: %user %nice %system %iowait %steal %idle 37.67 0.00 5.26 0.75 0.08 56.24 Device: tps Blk_read/s Blk_wrtn/s …
webgr
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What iowait values are ok?

I am trying to find the bottleneck of a server running a fairly busy php/mysql site. My first culprit was io but iostat shows that on average iowait consumes only %3.60 of cpu time. here is the complete result of issuing iostat: avg-cpu: %user …
alfish
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high iostat load on linux

atop: DSK | cciss/c0d0 | busy 87% | read 24193e4 | write 4076e4 | KiB/r 26 | KiB/w 77 | MBr/s 7.61 | MBw/s 3.78 | avq 6.07 | avio 2.49 ms | iostat Device: tps Blk_read/s Blk_wrtn/s Blk_read …
nateless
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What do the columns in you get from iostat mean?

When I perform the command iostat -x | grep -P 'Device|x.\s' I get the following columns as output device rrqm/s wrqm/s r/s w/s rsec/s wsec/s avrq-sz avqqu-s await svctm %util What does each of…
Chandam
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Is disk dying? Weird numbers on iostat

I have this old P4 box in my house with Ubuntu Server on it I use as a media server. Apart from the IDE boot drive there is a 1TB SATA disk attached with one of those el-cheapo IDE to SATA adapters like this one. The disk is supposed to be one of…
user34039
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What could cause high iostat await if a disk isn't overutilized?

I have a database running on GCP. Occasionally it gets very slow for a period of minutes (like average statement execution time spikes by 10x or more). The slowness is correlated with increases in the await output from iostat (system.io.await metric…
Ben Kuhn
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iotune qemu/KVM total_iops total_bytes limits

I have created some qemu/KVM virtual machines on SSDs. The host has ~6 SSDs. 1 is being used for the OS, and each of the other SSDs has two VM guests. I'm using iotune to limit the capabilities of these drives: …
turbonerd
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Difference in utilisation reported by iostat for two identical disks in RAID1

I'm trying to debug some weird behaviour with Postgres performance and am trying to understand the iostat output. I'm on 2x SSD on RAID1. Why would one of the disks be reported at ~21% utilisation and the other at ~95% utilisation? Shouldn't they…
Saurabh Nanda
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What does iostat show a different utilization for the 'dm' device?

I installed an M.2 drive into a Proxmox host this morning and monitored the disks with iostat -x 1. Why is iostat showing dm-7 is at 98% utilization, while the M.2 LVM PV (nvme0n1p1) shows only 6.8? I would expect, since dm-7 is a symlink the the…
Server Fault
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What are the parameters in iostat

I used iostat and trying to understand the iostat output using this link : https://linoxide.com/linux-command/linux-iostat-command/ but It is not clearly explained. PF the output at different times from 18:00:00 to 18:45:00 : We got the delay in…
Harry
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How to find good state io stats?

I would like to monitor disk I/O activity in case something courses heavy I/O. This Nagios plugin seams simple, where he gives examples of Example: Tps, read and write thresholds: ./check_diskstat.sh -d sda -w 200,100000,100000 -c…
Sandra
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