Is this IO Stat output good or bad?

abefroman · 08-09-2008, 10:29 AM

Is this IO Stat output good or bad?
# iostat
Linux 2.6.18-8.el5 08/09/2008

avg-cpu: %user %nice %system %iowait %steal %idle
4.56 0.53 8.30 51.18 0.00 35.43

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
hda 23.09 85.96 2570.76 4359814 130390468
hdc 49.49 1928.38 311.99 97808294 15824216
dm-0 327.06 85.82 2570.92 4353034 130398216
dm-1 0.00 0.03 0.01 1296 640

Mr. C. · 08-09-2008, 08:07 PM

There's not enough data here to give you an answer. If you are trying to benchmark your disk speed, download, compile, and use bonnie++.

trickykid · 08-11-2008, 01:31 PM

Actually, %iowait looks horrible with the information provided. If you have a consistent %iowait above 20.00, you should be concerned about your disk performance from my experience. From my understanding, that's the % of time the CPU is waiting on the disks to complete reads and writes to disk.

I also recommend bonnie++ or other utilities though, there have been issues/bugs with iostat providing full accurate information about system I/O.

chort · 08-11-2008, 02:30 PM

Look at hda blocks written per second and hdc blocks read per second. It looks like there's essentially a huge copy operation from hdc to hda. Of course performance is going to be bad, because you're blocking on disk I/O for pretty much everything while that cp is in progress.

PS using the CODE bbcode makes output much more readable. Try to use that in the future.