topic Re: Oracle 8i problem after memory upgrde in Operating System - HP-UX

Oracle 8i problem after memory upgrde

Richard Davies — Fri, 10 Dec 2004 03:49:44 GMT

Hi All

I have a server running HP-UX 11 (64bit) with Oracle 8i (32bit). There are 2 Oracle instances running (or were)live and test. The server had 1 GB memory installed and there was no problems. Yesterday we added an aditional 3 GB memory. Now the live instance starts no problem, but the test instance will not start, fails with

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

We haven't changed any Oracle or Kernel settings, anyone any ideas?

Thanks

Richard

Re: Oracle 8i problem after memory upgrde

bhavin asokan — Fri, 10 Dec 2004 04:25:22 GMT

hi,

there are somany posts regarding this
see the followinglinks,

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=135991

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=566727

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=314468

regds,

Re: Oracle 8i problem after memory upgrde

Massimo Bianchi — Fri, 10 Dec 2004 04:36:36 GMT

Hi,
32bits apps can address just the first 2G of RAM.

Did you increased the SGA of the live instance ?

If you want to use oracle in the 3rd and 4th Gb space addressing, you shuld use the memory windows... but they are a little complicated.

Consider that you can use the 64bit oracle, it would avoid you many problems like this.

Moreover: could you please post your kernel config (/stand/system) ?

I suspect some low kernel parameter...

HTH,

Massimo

Re: Oracle 8i problem after memory upgrde

Nguyen Anh Tien — Fri, 10 Dec 2004 06:11:43 GMT

I recommend You using Oracle 64bit. This verion can correct your problem.

Re: Oracle 8i problem after memory upgrde

Alexander M. Ermes — Fri, 10 Dec 2004 07:15:04 GMT

Hi there.
This is recalling some old stuff.
If you use 32-bit Oracle, the max SGA size is 1.75 GB FOR ALL databases together !
Sorry for the bad news.
You could go to windowing as alternate solution, but that is a different story and i would not go for it.
Rgds
Alexander M. Ermes

Re: Oracle 8i problem after memory upgrde

Steven E. Protter — Fri, 10 Dec 2004 07:29:25 GMT

I think Alexander is on to something there. If you reduce the SGA of the live database the test database may start.

The long term answer is 64 bit Oracle is the way to go. If there was a physical problem with the new memory it would not be possible to run the box.

If you go 64 bit your data's word size will have to be converted from 32 bit to 64 bit.

SEP

Re: Oracle 8i problem after memory upgrde

Hein van den Heuvel — Fri, 10 Dec 2004 08:54:13 GMT

Be sure to follow up the pointers to the old topics posted earlier. It has all been said and done before.

My guess is that you were just on the edge, and now need to tweak swap settings.

Just to try you might want to
- reverse the start order
- reduce the SGA dramatically ( 1/2 shared pool, 1/2 buffer).
Only to try... not to run.

check (real/swap) memory pressure as you go.
Also check ipcs -m

Alexander wrote : "If you use 32-bit Oracle, the max SGA size is 1.75 GB FOR ALL databases together ! "

I can not believe that at all. That _has_ to be bogus. / urban myth. That 1.7 limit is strictly a virtual address issue for the oracle image(s). Each instance has its own address use, its own shared memory section (ipcs -m). They are not mapped together.

hope this helps some,
Hein.

Re: Oracle 8i problem after memory upgrde

Massimo Bianchi — Fri, 10 Dec 2004 09:09:36 GMT

HI Hein van den,
it's not an urban legend.

32bit oracle can address just 2Gb of memory, but since 0.25 is used by the kernel itself, you are left with 1.75Gb. the FIRST 2Gb of memory.

Memory windows can be helpful, because you can shit those 1.75Gb, but the are not easy to handle.

There is a white paper in each hpux server //usr/share/doc/mem_wndw.txt ,
but you will have to trouble a lot.

Try playng with the swap, or install 64bit software. It's much easier.

HTH,
Massimo

Re: Oracle 8i problem after memory upgrde

Hein van den Heuvel — Fri, 10 Dec 2004 11:39:11 GMT

Looks like I was wrong. There is indeed a max of 1.7GB for the total SGA's. To do with share_magic.
The best documenation for this is probably in metalink artcle 69119.1 :
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=69119.1

Why do you have a problem now? Something else ate a little more space? As suggested before, try tweaking the SGA down a little. Try switching the startup order. See it any TRACE (and/or ALERT) file has more details.

How to solve it for real?
Go 64 bit, or use memory windows:

http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_id=77310.1&p_database_id=NOT

Cheers,
Hein.

Re: Oracle 8i problem after memory upgrde

Hein van den Heuvel — Fri, 10 Dec 2004 12:06:03 GMT

Folks,

Richard accidently launched 2 identical topics, with only a minor spelling change in the subject.

There is a also activity in:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=760500

I'd like the current thread (760502) to become the main one... if the discussion is not over.

fwiw,
Hein.