[CentOS] High load since passing from rhas3 to centos4.8
fergleiser at yahoo.com
Fri Jan 15 00:32:19 UTC 2010
----- Original Message ----
> From: "fortin.pierre at bell.ca" <fortin.pierre at bell.ca>
> To: centos at centos.org
> Sent: Thu, January 14, 2010 5:47:43 PM
> Subject: Re: [CentOS] High load since passing from rhas3 to centos4.8
> The purpose of the server is to run NMS Telephony cards. The only support is for
> Centos 4.x on 32 bit systems. Anyway, since I have not found the trouble, it may
> still be there with another centos version.
> When I execute multiple ps during high load average period (above 10), here is
> the kind of output I have:
> ps aux | grep " R"
> USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
> root 16295 0.0 0.0 3492 772 pts/1 R+ 15:45 0:00 ps -aux
> root 16296 0.0 0.0 5400 648 pts/1 S+ 15:45 0:00 grep R
> I see a lot of process in S, Sl, Ss+ and Ssl states.
first of all, if you have high load average with seemingly low utilization, it may be because of load imbalance between CPUs and/or short bursts of lots of short cpu-intensive processes.
Here's what I'd look at first:
run "vmstat 1 10" and look at the first column. if it's higher than 1/ncpu you're having cpu saturation.
rum "mpstat -P ALL 1 10", this gives you cpu utilisation per cpu (sar gives you the average among all processors)
Also take a look at "sar -q 1 10" to look at the CPU's queues sizes
Hope this helps
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