Description:
graph that shows iowait % on a per disk level. (Not satisfied by the CPU graphs IO plot).
It seems fair as a large % of DB slow down is when servers have high IO wait on disk(s).
Plotting the values such as;
# iostat -x
Linux 2.6.22.9-61.fc6 (dixon) 04/09/2008
avg-cpu: %user %nice %system %iowait %steal %idle
1.50 0.01 1.24 0.72 0.00 96.54
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 1.62 8.07 2.16 1.40 379.05 75.85 127.58 0.21 57.93 4.53 1.62
dm-0 0.00 0.00 3.75 9.48 378.96 75.85 34.38 3.53 266.61 1.22 1.62
dm-1 0.00 0.00 0.00 0.00 0.01 0.01 8.00 0.00 7.40 1.51 0.00
The util (last column, second section) column I find most useful. These would be really good alarms to fire on high % values too.
How to repeat:
.
Suggested fix:
Add IOwait graphs to monitor multiple disks on a system.
Description: graph that shows iowait % on a per disk level. (Not satisfied by the CPU graphs IO plot). It seems fair as a large % of DB slow down is when servers have high IO wait on disk(s). Plotting the values such as; # iostat -x Linux 2.6.22.9-61.fc6 (dixon) 04/09/2008 avg-cpu: %user %nice %system %iowait %steal %idle 1.50 0.01 1.24 0.72 0.00 96.54 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util sda 1.62 8.07 2.16 1.40 379.05 75.85 127.58 0.21 57.93 4.53 1.62 dm-0 0.00 0.00 3.75 9.48 378.96 75.85 34.38 3.53 266.61 1.22 1.62 dm-1 0.00 0.00 0.00 0.00 0.01 0.01 8.00 0.00 7.40 1.51 0.00 The util (last column, second section) column I find most useful. These would be really good alarms to fire on high % values too. How to repeat: . Suggested fix: Add IOwait graphs to monitor multiple disks on a system.