Re: 32 bit oracle on Solaris 9 64 bits ?

"Sean Chang" <sean_at_cnfei.com> wrote in message news:<3fa2908e_3_at_corp.newsgroups.com>...
> Comments inline.
>
> > I just bought a new sun server (280R) and I plan to run solaris 9 on it in
> > 64 bits mode,
> > which I think is the default when you install (Can anyone confirm this ?)
>
> Yes, 64-bit is the default. You should never change to 32 bit OS
>
>
>
> >
> > Should I run oracle 64 bits edition on it, or would oracle 32 bits edition
> > run just fine ?
>
> We run an Oracle DB of 32 bits in 64-bits Solaris (8 ,9) for more
> than 2 years now. Performace is good, also very stable.
>
>
> > I heard that the 64 bit edition was slower and I don't need a HUGE SGA,
> and
> > I will probably
> > have older 32 bit oracle OCI apps running that I cannot recompile.

Oooh, scary Halloween! :-O

They are supposed to work, but those shared libraries... you just never know until you try. Hopefully it will only be an issue when recompiling.

> >
> > Is there a HUGE performance penalty in running 32 bits apps on solaris 64
> > bits ?>
> Don't know that becuase I have no comparisons.

http://www.sun.com/sun-on-net/itworld/UIR951101perf.html

Metalink Note:107201.1 says "32-bit databases run on systems with a small number of 32-bit CPUs (4-6) may see some degradation in performance if moved to 64-bit systems also with a small number of 64-bit CPUs.

Applications will achieve the benefits of improved scalability on-64 bit machine only if they are memory intensive. 64-bit applications have bigger data structures because memory has to be addressed with a larger number of bits. Larger data structures translate into addtional memory requirements per process. ...

When running 32-bit Oracle binaries on a 64-bit machine, you will have to set SHMMAX to 1GB exactly. This is an important requirement when you want to extend the SGA beyond the 1GB. "

Note that you can have a huge SGA with 64-bit, if you can afford the physical memory and checkpointing penalties. The general idea is that not having to go to disk is an advantage over the penalties. For the same init.ora configuration, 64 bits will need more physical memory.

http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=209766.1

Watch the Oracle certification matrix for bit availability when upgrading.

http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=62290.1

My general bias is spring for the physical memory and run 64 bit, since most businesses eventually want to calculate things. And don't run unsupported software that has no ability to recompile/reinstall.

jg

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