Odd sar output

Williams, David A. - DAWilliams DAWilliams at aarp.org
Wed Feb 28 11:27:07 CST 2007


Jeff,
	I would believe it was a new task or cron job except this
happened days ago and sar continues to report 0% idle CPU overall but
mid to high 90s idle on each of the virtual CPUs.  At this point I'm
flummoxed by the "all" CPU line not relating clearly to each of the
virtual CPUs.
	-David


Jeff Howell wrote:

It's probably a cron job like updatedb running. You'll note an increase
in %system and %iowait indicating significant disk activity. 

Hope this helps,
Jeff 

-----Original Message-----
From: linux-poweredge-bounces at dell.com
[mailto:linux-poweredge-bounces at dell.com] On Behalf Of Williams, David
A. - DAWilliams
Sent: Tuesday, February 27, 2007 12:54 PM
To: linux-poweredge at dell.com
Subject: Odd sar output

	We have a set of dual CPU 2850s in production and we keep an eye
on sar on each of them.  One, which is not heavily used, has started
returning really odd things from sar.  Between 14:20 and 14:30 the
combined idle time dropped from ~ 93% (where it had been since going
into production) to 0 and it has stayed at 0 for the last several days.
But the 4 individual virtual CPUs don't show any real change.  Does this
make sense to anyone?  Has anyone else seen this behavior?

Heading           CPU     %user     %nice   %system   %iowait     %idle
14:20:01          all      5.47      0.00      0.80      0.27     93.47
14:20:01            0      4.71      0.00      0.72      0.11     94.46
14:20:01            1      4.35      0.00      0.79      0.16     94.70
14:20:01            2      4.80      0.00      0.57      0.17     94.46
14:20:01            3      5.46      0.00      0.74      0.53     93.28

14:30:01          all     82.62      0.00     14.46      2.92      0.00
14:30:01            0      4.62      0.00      0.71      0.22     94.45
14:30:01            1      5.88      0.00      0.63      0.00     93.48
14:30:01            2      2.04      0.00      0.68      0.11     97.17
14:30:01            3      1.81      0.00      0.49      0.18     97.52

14:40:01          all     84.66      0.00     13.67      1.68      0.00
14:40:01            0      3.12      0.00      0.68      0.04     96.16
14:40:01            1      5.17      0.00      0.57      0.00     94.26
14:40:01            2      3.41      0.00      0.59      0.02     95.98
14:40:01            3      3.29      0.00      0.59      0.23     95.90

	Thanks for any pointers,
	-David
---------------------------
David Williams
Director, Internet Technology
Web Strategy and Operations
AARP Services
(202)434-3672
dawilliams at aarp.org
http://www.aarp.org/ 

---------------------------
David Williams
Director, Internet Technology
Web Strategy and Operations
AARP Services 
(202)434-3672
dawilliams at aarp.org
http://www.aarp.org/ 



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