Red Hat

Hi,
I have set up sar on my RedHat and Fedora Linux systems. I am running sa1 from cron:

Code:

0 8-17 * * 1-5 /usr/lib/sa/sa1 1200 3 &

The 1200 and 3 parameters tell sa1 to save data every 1200 seconds (== 20 minutes) and to write 3 times.

When I run sar to observe my data, I'll see something like this:

Code:

# sar -A -f /var/log/sa/sa22 | more
Linux 2.6.21-1.3228.fc7 (opchux0011.comp.optiver.com)   10/22/2008

12:00:01 AM    proc/s
12:10:01 AM      0.03
12:20:01 AM      0.03
12:30:01 AM      0.03
12:40:01 AM      0.03
12:50:01 AM      0.03
01:00:01 AM      0.03
01:10:01 AM      0.18
01:20:01 AM      0.03
01:30:01 AM      0.38
01:40:01 AM      0.03
01:50:01 AM      0.03
...

...What gives? Why is it reporting data every 10 minutes? How come I only see 1 entry every 10 minutes, and not 3? I'm confused...

Thanks.
-mschwage

Did you add this cron job yourself, or did you just use the one that was installed by sysstat (usually in /etc/cron.d/sysstat)? Maybe there's another job running that's recording data every 10 minutes.

You shouldn't see 3 entries every x minutes anyway... the 3 just means that it should write 3 entries 20 minutes apart. i.e. first cron job of the day runs at 08:00, collects data for 1200 seconds, writes an entry, collects data for 1200 seconds, writes second entry, collects data for 1200 seconds, writes third entry and exits... at which time it would be 09:00 when the next cron job kicks in and repeats the exercise.

So the only mystery here is why it's recording at 10 minute intervals... unless sar insists on reporting in 10 minute intervals by default, but I didn't think it could do that unless the data was actually recorded with that frequency.