topic Re: Memory Usage in Operating System - HP-UX

Memory Usage

Jason Cornell — Fri, 20 Feb 2004 11:33:46 GMT

I have a J5600 Workstation running HPUX11i with 1Gb RAM.

When running vmstat from a fresh reboot it displays:

# vmstat 5 5
procs memory page faults cpu
r b w avm free re at pi po fr de sr in sy cs us sy id
1 0 0 174328 14385 16 13 22 0 0 0 11 437 896 98 1 1 98
1 0 0 174328 14329 0 0 0 0 0 0 0 413 171 40 1 0 99
1 0 0 155934 14329 0 0 0 0 0 0 0 407 116 28 0 0 100
1 0 0 155934 14329 0 0 0 0 0 0 0 413 249 30 0 0 100
1 0 0 173308 14329 0 0 0 0 0 0 0 407 131 25 0 0 100
#

We have 1 Oracle db loaded which supposedly uses abouut 300Mb. Where could my other 700Mb of memory have gone ?

Re: Memory Usage

Steven E. Protter — Fri, 20 Feb 2004 11:48:42 GMT

Take a look top command for whats using what.

Or do some more detailed measuremen with the scripts I'm attaching.

SEP

Re: Memory Usage

Patrick Wallek — Fri, 20 Feb 2004 11:52:09 GMT

The system will use some for system processes. There will be some used by the buffer cache.

If you have Glance invoke it to see what your real memory usage is. One good thing right now is that your 'po' column is still 0 so you are not paging out to your swap space. You can check 'swapinfo -tam' to make sure you are not, or have not been, paging out to the swap area.

You could check the setting of dbc_max_pct. If it is still 50 you could probably lower it to 25 or 30 and free up 200-250 MB of RAM.

Re: Memory Usage

Graham Cameron_1 — Fri, 20 Feb 2004 12:05:17 GMT

How do you know Oracle is using 300Mb?
Be aware that it will be using some shared memory for its SGA (shared global area), and some memory to run its processes.

You can see the all shared memory with "ipcs -ma". The OWNER col will be the oracle owner, and the SEGSZ col is the no of bytes allocated.

To look at the process memory usage, try "ps -luoracle" (assuming your oracle owner is "oracle", and look at the SZ column.

BTW 1Gb for oracle is not that much!

-- Graham

Re: Memory Usage

Geoff Wild — Fri, 20 Feb 2004 13:43:30 GMT

Run this to see top memory users:

UNIX95= ps -e -o 'vsz pid ruser args' |sort -nr|head -30

What is value of DBC_MAX_PCT?

Rgds...Geoff

Re: Memory Usage

Sundar_7 — Fri, 20 Feb 2004 13:47:53 GMT

Hi,

The rest of the memory may be used by the following components

1) Memory used by the system (kernel structures)
2) Shared memory
3) Shared mapped files by the user processes
4) Private mapped files by the users processes
5) buffer cache

Download the attache procsize.sh utility. Will give u the amount of memory used by each process (private as well shared mapped files).

-- Sundar

Re: Memory Usage

RAC_1 — Fri, 20 Feb 2004 13:50:42 GMT

glance -m will also give more details.

like

Total VM : 758.0mb Sys Mem : 1.12gb User Mem: 606.2mb Phys Mem: 4.00gb
Active VM: 384.8mb Buf Cache: 2.00gb Free Mem: 296.1mb

Re: Memory Usage

nibble — Sat, 21 Feb 2004 17:43:44 GMT

try to use glance