[CentOS] High system load but low cpu usage
Steven Tardy
sjt5 at its.msstate.edu
Thu Jun 9 13:49:40 UTC 2011
On 06/08/11 02:26, Emmanuel Noobadmin wrote:
> Cpu(s): 4.1%us, 2.5%sy, 0.0%ni, 76.4%id, 17.0%wa, 0.0%hi, 0.1%si, 0.0%st
> 02:50:01 PM all 2.17 0.00 2.18 4.30 0.00 91.35
> 03:00:01 PM all 2.47 0.00 2.23 3.57 0.00 91.73
top Cpu(s) line is averaged for all cpus/cores. to display individual cpus/cores press:
1
you'll likely see one cpu/core being pegged with iowait.
to identify the offending process within top press:
fj<enter>
to display the P column(last used CPU).
watch top for a few minutes to see what is using all of the disk io.
sar output is averaged over the 10 minute interval.
for smaller sar time slices edit cron file: /etc/cron.d/sysstat
disks are often swamped by "two things happening at once"...
backups
migrating a VM
database upgrades
.rrd average updates
--
Steven Tardy
Systems Analyst
Information Technology Infrastructure
Information Technology Services
Mississippi State University
sjt5 at its.msstate.edu
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