Re: Real life memory limits under UNIX/Linux

From: Christo Kutrovsky <kutrovsky.oracle_at_gmail.com>
Date: Thu, 9 Jun 2005 17:53:04 -0400
Message-ID: <52a152eb05060914535144f0a8@mail.gmail.com>

Tim,

We have multiple databases running (9i and 10g) on multiple RH versions (2.1 and 3.0).

The systems we have are as follow (assuming max memory for OS):

- no tricks, SGA - 1.9 gb, pga ~ 1 gb per sessions=20
- lowered base, SGA - 2.6 gb, pga ~ 300 mb per session
- indirect buffers (memory file system - slower) - 16 gb (thats what

we have, can probably go more), not sure about limit, pga - 1 gb.

Note those are per instance. You can have multiple instances and each can use that much.

Of course things are much more relaxed in 64 bit, but Oracle is not quite there. Important patches are missing from 64 bit versions.

Regards,
Christo Kutrovsky
Database/System Administrator
The Pythian Group

On 6/9/05, Tim Onions <att755_at_hotmail.com> wrote:
> Dear All

>=20
> I'm looking for a little guidance. Having lived (suffered) as an Oracle D=
BA
> on Windows 2000/2003 32bit for too long I'm now proposing to the board we
> should move to a "proper" environment. My main gripe with Windows is the
> memory architecture and how the single Oracle.exe process has to live wit=
hin
> 3Gb on 32bit. Sure 64bit ups that but if we have to move why not consider
> all options not just blindly follow MS?

>=20

> I'm trying to put together what the real limits in memory are under Unix
> (probably HP-UX as HP are our main supplier) and Linux (RH looks soooo go=
od
> on paper when comapred with MS). I've trawled the relavant home pages and
> got some good info but some tends to be contradictory if not downright
> unclear. Initially we'd use Oracle 9i as I'm not comforatble with 10g yet=
.
>=20
> What I would like is some guidance (or pointers to good trustworthy FAQs)=
 on
> how much memory each Oracle process can use - for instance 32bit RH Linux
> says 4Gb per process but does the OS steal any (coz Windows would). Or is
> that really 4Gb per process - so if I had 64Gb in the machine I get 4Gb f=
or
> a number of oracle process should I need them. I am going to get question=
ed
> on that when I make my proposals and would like hard facts not vendor
> "promises". Also are there any other gotchas I need to know about (and ca=
n
> relate plenty in Windows I can assure you). Yes I'm naive when it comes t=
o
> such things on Unix/Linux!

>=20

> Thanks for even reading this far!

>=20

> Tim

>=20


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>=20

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--=20
Christo Kutrovsky
Database/System Administrator
The Pythian Group

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Received on Thu Jun 09 2005 - 17:58:18 CDT