vmstat result-> system performance

[Nguyen Anh Tien]

I gather some vmstat result during 08/20/2004 to 08/27/2004. I set crontab runing with interval be (10 min x6 time). I found that at Business hour my server have some page out. But I do not know whether it is normal or bad. What formula can I calculate â avmâ parameter in v

[Eric Antunes]

I think one of the most important results is to verify if you have no many processes blocking. That's the value under the b letter:

procs
r b w
2 0 0

[Geoff Wild]

"sar -w 30 10" will report system swapping and switching activity.

# vmstat 2 100

Will show you your virtual memory metrics. sr should be very low
(0-5) po should also be low (0-5).
pi (page ins) are OK, it is the pageouts you need to be concerned about.


Rgds...Geoff

[Sridhar Bhaskarla]

Hi,

You may find some paging activity due to memory mapped files. I would check the following to confirm memory pressure on my systems if all the following conditions are true.

1. If the free memory is too low. Multiply 'free pages' in vmstat output with 4k and you will get that number. Or use glance.

2. If the 'po' rate is constantly above 10 in vmstat output.

3. If the "KB Used" column is non-zero in 'swapinfo -dft' output.

If you have lots of free memory and if you are still seeing paging activity, then it's due to memory mapped files and I would simply ignore it.

Check dbc_max_pct to see if it is not left at 50%. That's not needed.

-Sri