topic Re: Memory utilisation question in Operating System - HP-UX

Memory utilisation question

Vasago — Tue, 29 Jun 2004 10:32:18 GMT

hi,

Server is HP-UX 11.23 running Oracle 9.2
here is mem stat (by glance) :

Total VM : 3.27gb Sys Mem : 993.3mb User Mem: 1.53gb Phys Mem: 3.99gb
Active VM: 1.28gb Buf Cache: 1.47gb Free Mem: 26.3mb

Free MEM : 26.3 MB 6?? : Somebody can tell me if memory is misconfigured ?

How i can sort all process list with memory taken per process ?

Oracle is used 1.5 Go...

thanks

Re: Memory utilisation question

RAC_1 — Tue, 29 Jun 2004 10:39:01 GMT

Check the buffer cache settings. dbc_max_pct by default is at 50 %. (That means half of the memory is used for buffer cache.)

Check if you are effectively using it or not??

sar -b 2 20

If write cache rate is constantly over 90 %, it is OK else just tune the setting to 10 %.

You will have more memory availbel to users.

Anil

Re: Memory utilisation question

A. Clay Stephenson — Tue, 29 Jun 2004 10:41:31 GMT

With HP-UX the first thing one should always do is look at the dbc_max_pct value (50% by default). In almost every case, 50% is much too high and should be reduced to a more reasonable value (~10%) or hard-set via a non-zero bufpages setting.

Here is a method of sorting processes by memory usage:

UNIX95= ps -e -o vsz,comm | sort -n

Man ps for details. The "UNIX95= " asserts the XPG4 ps behavior for just this command.

Re: Memory utilisation question

Vasago — Tue, 29 Jun 2004 12:35:15 GMT

thanks guy, that resolved my problem

but the swap util had growed from 40 to 50 %...

did this ratio report to swap file utilisation or sometingelse?

Re: Memory utilisation question

Sundar_7 — Tue, 29 Jun 2004 12:59:59 GMT

Obviously it is your swap util that increased to 50%.

With only 26.3 MB available for the user processes, you are sure to have lot of paging activities in the system.

As mentioned above, release the space from dynamic buffer cache. That should solve your problem or get you somewhere nearby.

Re: Memory utilisation question

RAC_1 — Tue, 29 Jun 2004 13:16:26 GMT

Every process that starts, will reserve the swap space. So in case if it has to swap out, it will have required space.

Now after setting dbc_max_pct to 10 %, more memory will be availbe to users, so you can start ore processes and so the swap space utilization.

Anil