topic Re: ram utilization in Operating System - HP-UX

ram utilization

MOI_1 — Wed, 20 Feb 2002 13:20:06 GMT

Hi,
this is my first time in this site, hope you help me.
i have hp9000 server with 2GB ram and 4 proc. 350, raid 5 storage. the application running on the server is oracle 8i.
i have 440 users connected i face a problem in the ram in which it is always 100% used and swaping up to 95% swap area is 5 GB. glance show always 100% of ram used and users complain from slowlinace of the system advice me what to do

Re: ram utilization

Peter Kloetgen — Wed, 20 Feb 2002 13:23:43 GMT

Hi,

this may be caused by wrong settings for kernel parameters. Did you change parameters when installing Oracle? If yes, please post the values here. Swapspace seems sufficiant so there must be other reasons.

Allways stay on the bright side of life!

Peter

Re: ram utilization

Ian Dennison_1 — Wed, 20 Feb 2002 13:27:08 GMT

I suppose there are many ways to investigate this.

How much buffer cache is being used (dbc_max_pct & bufpages)? If this is overallocated, you can save some memory by reducing it to approx 400MB. (20% of memory).

What does 'vmstat' show for page in and page out? (po & pi).

What is the SGA area ('show sga' command in 'svrmgrl')?

Is this increase in usage sudden or gradual?

Share and Enjoy! Ian

Re: ram utilization

John Downs_1 — Wed, 20 Feb 2002 13:41:09 GMT

I recommand the following:

1. Is this a new problem? Did something change on the system or did it gradually degrade? If is the former you may consider backing out the change. If its the later you may need more resources, memory, swap, cpu...

Other approaches:

2. Find out which application is using
all the memory/cpu. Use ps and top.

2. Once you've identified this process or
processes. Ask youself or the vendor:
should this application be consuming
this much of the machines resources?

3. If the answer is no, maybe the application
is misconfigured or in a bad state.

4. If its the configuration work with the vender to fix it. If you think its the later, you may consider rebooting if the machine has been up for a long time.

Good Luck
-john

Re: ram utilization

Krishna Prasad — Wed, 20 Feb 2002 13:56:20 GMT

Can you attach your

/stand/system file
initSID.ora file

Has statistics been run on the Oracle tables?

Are datafiles and indexes on the same physical drives?

What is the application you are running? Is it a custom application that uses Oracle? Is it a package solution? Does it have any startup/configuration files that may need adjusted?

Re: ram utilization

harry d brown jr — Wed, 20 Feb 2002 14:32:47 GMT

MOI,

First check to make sure you have the following kernel parameters near these values:

dbc_max_pct = 10
dbc_min_pct = 5

Secondly, 2GB of ram for 440 Oracle users is totally inadequate. Think of it this way, if every user consumed only 5 MB of memory, that would require at least 2.2 GB of memory, but we know that user processes usually consume more, so at 10 MB, you need at least 4GB.

HP memory mgt paper:
http://docs.hp.com/hpux/onlinedocs/os/11i/mem_mgt.html

Oracle Tuning guide:
http://www.quest.com/whitepapers/oracle_perf.pdf

live free or die
harry

Re: ram utilization

Stefan Farrelly — Wed, 20 Feb 2002 15:22:10 GMT

Youre completely out of RAM. When you do a swapinfo command you want the USED column to be 0 (ZERO).

Ways to fix;

1. Add more RAM
2. Reduce buffer cache (dbc_max and dbc_min kernel parameters)
3. reduce size of SGA for your oracle databases (DBA can do this)