IO load takes IO wait into it's calculation, so it may be a writer process hammering the disks which are under powered for the IO load.

Run an iostat under these situations to find the disks causing the high waits.

-Ross

-----Original Message----- From: centos-bounces@centos.org centos-bounces@centos.org To: CentOS mailing list centos@centos.org Sent: Wed Dec 05 09:39:41 2007 Subject: [CentOS] weird load values

Hi List,

I'm stumped by this:

load average: 10.65, 594.71, 526.58

We're monitoring load every ~3 minutes. It'll be fine (i.e. something like load average: 2.14, 1.27, 1.03), and then in a single sample, jump to something like the above. This seems to happen once a week or so on a few different servers (all running in a similar application). I've never seen the 1 minute sample spike as high as the 5 or 15 minute samples.

Seeing as that last value is a 15 minute period, well, it doesn't seem possible that one can have a 500+ 15 minute sample without having observed a spike in the 5 minute sample at least 5 minutes before.

Also, there aren't 500+ processes on these systems -- it's typically around 100 total processes (ps auxw | wc -l). (Is there a way to see the total count of kernel-level threads?)

Thoughts?

best, Jeff

Linux someHostName 2.6.18-8.1.8.el5 #1 SMP Tue Jul 10 06:39:17 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux

CentOS release 5 (Final)

09:31:15 up 65 days, 17:45, 2 users, load average: 0.92, 200.91, 371.30

_______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos

______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.