Questions tagged [iostat]
92 questions
18
votes
7 answers
How can I map iostat device names to LVM /dev/mapper/XXX names?
mount shows mount devices like:
/dev/mapper/VolGroup01-LogVol00 on /var type ext3 (rw)
or
/dev/mapper/VolGrp_backups-backups on /mnt/backups type ext3 (rw)
but
iostat uses dm- notation. like dm-0, dm-1 and so on.
Where can I find a way to know…
user13185
12
votes
1 answer
what percentage of iowait is considered to be high?
when iowait is considered to be high ?
iostat -x
avg-cpu: %user %nice %system %iowait %steal %idle
2,89 0,01 5,45 49,83 0,00 41,83
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz …
Gabriel Sousa
- 307
- 2
- 4
- 10
12
votes
2 answers
can someone explain IOSTAT ouput?
i'am having IBM server with Redhat 5 ElsmP connected to the IBM Storage over iSCSI (in sdb ) can someone explain this output from iostat command
avg-cpu: %user %nice %system %iowait %steal %idle
12.79 0.01 4.53 72.22 0.00…
dani.jtk
- 141
- 1
- 1
- 5
11
votes
1 answer
(A Windows guy asks) Measuring Disk Latency on Linux: Do I bother?
On Windows, whenever I want to validate / confirm that there might be IO-related issues on a volume that a database or other low-latency app lives on, I check disk latency.
If I see the Windows Average Disk sec / Transfer counter > 18-20ms…
Russell Christopher
- 485
- 5
- 10
10
votes
3 answers
Extremely Slow IO with Simple PostgreSQL 8.4.4 Queries on Centos 5.5
The strange and extremely slow IO pattern I'm seeing is this (output of iostat -dxk 1 /dev/xvdb1):
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util
xvdb1 0.00 0.00 0.99 0.99 …
ehsanul
- 427
- 1
- 8
- 19
9
votes
1 answer
Windows "iowait" CPU utilization reporting
Does Windows account for and report "iowait" in the same manner as Linux? That is, processes enter "uninterruptible sleep" and their time spent is subtracted from "CPU free"?
If so, which Perfmon counters would be appropriate to detect "cpu busy due…
Yolo Perdiem
- 606
- 1
- 5
- 14
7
votes
4 answers
How to get iostat of a single process
How can I get iostats io throughput of just a process to try know if this process starts burning my HDD.
Thanks!
enedebe
- 1,006
- 3
- 11
- 17
6
votes
3 answers
Trouble interpreting iostat's tps measure
Prelude:
I dumped a 5.2 GB database using the mysqldump command. I did this on an underpowered virtual server with only 512 MB of memory. It took about an hour. I'm now reloading that database on my desktop machine that has a dual core cpu and 2 GB…
dvogel
- 301
- 1
- 2
- 4
6
votes
4 answers
Cannot see graphs for IO Service time and IOstat in munin
For some reason data & graphs for IO Service time and IOstat do not show up in munin. All other graphs are fine.
Can some one suggest me how to set munin to show the stats and graphs for these. Am I missing any packages?
RajeshT
- 163
- 1
- 4
5
votes
3 answers
What does it mean if iostat shows 100% busy wait but the CPU is completely idle?
What does it mean if iostat shows 100% busy wait but the CPU is completely idle? My application runs for a while, then goes into this state periodically for about 10-20 seconds.
It is transaction processing C++ app on solaris 10.
IO stat output:
…
sean riley
- 151
- 1
- 2
- 6
5
votes
4 answers
How can I find which process is causing this IO read (tried iotop already)
I've got a constant 1.4 megabytes/sec of IO read on one server (see iostat output below). What can I do to find which process is the cause ? I already tried iotop and htop, but could not pinpoint the issue with thoses:
Linux 2.6.35.4-x86_64-linode16…
Thibaut Barrère
- 651
- 1
- 9
- 17
5
votes
1 answer
iostat how do I set up a logging
Hi there I am pretty newbie in servers, would appreciate your help.
How do I set up an iostat logging? as my Disk IO spikes strange at some random time to very high levels.
Thanks.
simple
- 53
- 1
- 5
5
votes
1 answer
Are my drives being utilized equally with Linux Software RAID 0 array?
I have four NVMe drives in a RAID 0 configuration.
I am attempting to determine how many IOPS the array is handling.
When I run iostat, it appears that one drive is handling more IO than the other three drives.
Is this an error with the way that…
Vincent Saelzler
- 51
- 1
4
votes
3 answers
iostat - How does %util affect %idle and %iowait
Looking at iostat, if the system needs to issue a request for io, but has not yet been able to do so due to %util being pegged, would that wait be counted as %idle or %iowait?
modsiw
- 76
- 1
- 3
4
votes
3 answers
Linux utility to record IO statistics (random/sequential, block sizes, read/write ratio)
As part of provisioning our new server (see other SF) I'd like to find out the following:
ratio of random to sequential reads & writes
amount of data read & written at a time (pref in histogram form)
I can already figure out our reads/writes on a…
Michael Pearson
- 145
- 3
- 8