{{parent page="GeneralUnix"}}

===Sar===
sar is a useful command from the sysstat package which captures your system usage. The following example dumps system usage to a file every 10 seconds for 100 times -

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$ sar -u -o sar.out 10 100
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To read the statistics contained in that file
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$ sar -f sar.out
Linux 2.6.22.6 (x.x.corp) 10/11/2007

03:11:47 PM CPU %user %nice %system %iowait %steal %idle
03:11:49 PM all 4.00 0.00 0.50 0.00 0.00 95.50
03:12:08 PM all 8.00 0.00 2.50 30.50 0.00 59.00
Average: all 5.28 0.00 1.40 4.11 0.00 89.21
%%

== Sar and cron ==
Redhat by default creates these cron entries to capture system usage with sar. It's placed under /etc/crond.d

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# run system activity accounting tool every 10 minutes
*/10 * * * * root /usr/lib/sa/sa1 1 1
# generate a daily summary of process accounting at 23:53
53 23 * * * root /usr/lib/sa/sa2 -A
%%