topic Re: Two Oracle instances not coexisting in Operating System - HP-UX

Two Oracle instances not coexisting

Rodger Devillier — Thu, 24 Aug 2000 15:06:20 GMT

I have a 2-node ServiceGuard cluster with two packages. Each has an Oracle instance - completely separate installs. They each come up just fine on each node if they are the only instance running. The second instance to attempt startup gets:

ORA-27102: out of memory
HP-UX Error: 12: Not enough space

The servers are N-class with 16GB of memory; shmmax is set to 1GB. Each of the instance's SGA is 1.5GB.

Does anyone have any ideas as to why the second instance fail? Is it a shmmax problem?

By the way, I'm not Bryan - I'm Dana Manda.
Thanks.

Re: Two Oracle instances not coexisting

Vikas Khator — Thu, 24 Aug 2000 15:08:43 GMT

Hi ,

Try increasing your maxdsiz . That may solve some of your out of memory issues.

Re: Two Oracle instances not coexisting

Stefan Farrelly — Thu, 24 Aug 2000 15:16:17 GMT

Errno 12; not enough core usually always means your out of swapspace. Try adding some more and/or turning on the following kernel parameter SWAPMEM_ON is set to 1.

Re: Two Oracle instances not coexisting

Antoanetta Naghiu — Thu, 24 Aug 2000 15:20:36 GMT

Hi Dana,
If your Oracle configuration is ok to run two concurent instances, could be a kernel params issue.
For HP11, going in sam->kernel Parm->configurable param->action->temlpates->apply tuned param set->general OLTP/Database Server System can help you a little bit.
Also, you can take a look at:
http://docs.hp.com/hpux/content/KCparams.OverviewAll.html
As well you can check the forum for Kernel as a key word and you'll get lots of posts.
Chris Anoruo attached a few times a list of kernel params.
Good luck!

Re: Two Oracle instances not coexisting

Anthony deRito — Thu, 24 Aug 2000 15:31:44 GMT

Dana, before you change maxdsize note that this message is usually indicative of the memory manegement subsystem not being able to "reserve" enough virtual memory for the running process. Use swapinfo -tma on both machines and check out your PCT USED column for the "total" entry. See if there is enough memory available to reserve. The kernel won't allow this process to run unless the memory management subsystem tells it that is was able to reserve enough virtual memory in case it needs to be swapped out. Also, check if swapmem_on kernel parameter is set differently on each system.

Tony

Re: Two Oracle instances not coexisting

CHRIS_ANORUO — Thu, 24 Aug 2000 15:33:34 GMT

DANA,
Set these values as follows:
MAXDSIZ=IGB
MAXTSIZ=1GB
NBUF=0
BUPAGES=0
DBC_MAX_PCT=25
DBC_MIN_PCT=5
SWAPMEM_ON=1
ALLOCATE_FS_SWAPMAP=0
SHMMAX=1GB
SEMAEM=16384
SEMMAP=1366
SEMMNI=1364
SEMMNU=2048
SEMVMX=32767

I hope your total swap space is upto 3gb.

See link
http://www.docs.hp.com/hpux/content/KCparams.OverviewAll.html

Re: Two Oracle instances not coexisting

Vince Inman — Thu, 24 Aug 2000 15:46:06 GMT

Your problem is a result of the SGA config's for Oracle exceeding the shared memory available on the server. If you are running Oracle 32-bit you will not be able to
address more than 1.87 GB of shared memory (which happens to be the limit for shared memory on 32 bit 10.20 of HP-UX). This would not be the problem if you were running 64-bit ORacle.

You can get around this problem (with 32-nit Oracle) by limiting your TOTAL SGA usage to less than approx. 1.8GB of SGA space. Alternatively you can implement what is known as memory windows on HP-UX 11 that will allow each instance to utilize up to 1.87 GB of SGA space. I've only had to use this in one shop that I've worked in.

Re: Two Oracle instances not coexisting

CHRIS_ANORUO — Thu, 24 Aug 2000 15:55:45 GMT

Hi Dana,

Check this link also, I don't think you will have shared memory problems if you follow the settings as recommended. http://my1.itrc.hp.com/cm/QuestionAnswer/1,1150,0xb05f7e990647d4118fee0090279cd0f9,00.html

Re: Two Oracle instances not coexisting

CHRIS_ANORUO — Thu, 24 Aug 2000 16:22:03 GMT

Re: Two Oracle instances not coexisting

Wodisch — Thu, 24 Aug 2000 22:03:04 GMT

Hi Dana,
do you use a 32bit Oracle? Then read the docu about "Applications Domains" or
"Memory Windows" and use the "setmemwindow" command with a different
number for each of your instances. That way you will get independent shared
memory segements for the instances! But that accounts only for the 1GB segment
for the "shared data" quadrant, so you might only be able to have two 1GB SGAs!
HTH,
Wodisch