Questions tagged [iostat]
92 questions
4
votes
7 answers
How do I tell which processes are writing heavily to disk in CentOS 5?
Our server started getting slow, so I ran iostat on it.
iostat -dx 5
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 89.60 108.40 5.60 880.00 763.20 14.41 …
Artem
- 173
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3
votes
1 answer
Why are cpu usage percentage different between top and iostat?
On a heavily loaded database server, I am getting vastly different output from top and iostat for cpu usage. Why might the value be different?
top:
%Cpu(s): 84.7 us, 11.8 sy, 0.3 ni, 2.4 id, 0.6 wa, 0.0 hi, 0.2 si, 0.1 st
iostat
avg-cpu: …
AgDude
- 181
- 7
3
votes
0 answers
Why are /proc/diskstats figures suddenly unbelievably low?
I have a Debian jessie server with two Intel DC S3610 SSDs in it, in RAID-10. It's reasonably busy for IO and for the last several weeks I've been graphing the IOPS:
As you can see, most of the time it was happily doing about 1k average read ops…
grifferz
- 928
- 5
- 13
3
votes
2 answers
Reporting historical system activity in FreeBSD
I'd like to record data about system activity under FreeBSD for future analysis. If I were running a SysV system, I'd just sar and its related utilities, but that doesn't exist in the BSDs. (And bsdsar has gone missing.) I don't really care about…
wfaulk
- 6,828
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3
votes
1 answer
How to know which row in fstab need to be changed to relatime/noatime?
If I run iostat I saw this:
avg-cpu: %user %nice %system %iowait %steal %idle
15.36 0.78 9.66 21.46 0.00 52.74
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 180.34 494.08 …
user4234
- 303
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- 16
3
votes
2 answers
How iostat figures out to take CPU idle time to consider as %idle or %iowait?
I was going through iostat man page. According to it,
%iowait
Show the percentage of time that the CPU or CPUs were idle during which the system
had an outstanding disk I/O request.
%idle
Show the percentage of time that the CPU or CPUs…
pradeepchhetri
- 2,518
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3
votes
2 answers
How to install iostat to Red Hat 5, without internet connection?
Title is pretty clear, I have a server which doesn't have an internet connection. So I can't use yum or anything like that. I want to download necessary files with my PC and upload to server via SSH and then install it.
But I don't know, where to…
ramazan polat
- 148
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- 10
3
votes
2 answers
iostat: See current usage rather than average
I need to log disk statistics (MB/read, MB/write) of block devices. As I understand, iostat shows an average value. This is not exactly what I want when I'm about to monitor a server. Is there a way to show current values rather than the…
Daniel
- 2,877
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3
votes
2 answers
iostat on Solaris with ZFS - why is wait and %w always zero?
We have a busy server, chocking under a high IO load, at least, that's the feeling I have. Output from iostat -xz looks like this:
extended device statistics
device r/s w/s kr/s kw/s wait actv svc_t %w %b…
shlomoid
- 289
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3
votes
1 answer
Is the sum of IOPS for individual physical disks not equal to the raid0 logical disk?
I have a raid0 set up consisting of 2 physical disks:
bash-4.2$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 100G 0 disk
`-xvda1 202:1 0 100G 0 part /
nvme0n1 259:0 0 1.7T 0 disk
`-md0 9:0 0 3.5T …
user3098466
- 33
- 4
3
votes
0 answers
Can iostat output show mismatched read data for mdadm raid5 array?
I'm trying to understand this iostat output:
tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device
500.30 58.9M 19.4k 0.0k 329.1G 108.5M 0.0k sdc
500.26 58.9M …
JoeSlav
- 89
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- 10
2
votes
0 answers
Resetting disk table in zfs pool
In Our Solaris 11.3 zfs storage server, one disk in the pool died, we replaced it. Everything is working fine, but iostat is still showing old disk with large error count. This is bothering our monitoring scripts. Any idea how to reset disk list to…
Vinod Gupta
- 21
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2
votes
2 answers
physical vs logical disk transactions
I'm trying to analyze server requirements for a set of virtual machines. We're using LVM on them, so iostat shows numbers for both the logical volume and the physical disk, and they often don't match at the transaction level, and I'm trying to…
abatie
- 93
- 9
2
votes
1 answer
HP UX iostat on File System
I have a server running HP UX 11 OS and I'm trying to have I/O statistics for File System and not disk.
For example, I have 50 disk attached to the server when I type iostat (here under output of iostat for 3 disks) :
disk9 508 31.4 …
got2be
- 21
- 1
2
votes
1 answer
iostat taking lot of time to return
I have a solaris 10 server with a lot of SAN disks (close to 1000 across all paths). iostat -En takes close to 5 min to return. Is there a way to figure out what is causing the delay? truss hasn't helped much.
sai garimella
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