| MAX SGA Limit on Linux 32-bit [message #461746] |
Mon, 21 June 2010 05:07  |
paradoxkhan
Messages: 92
Registered: April 2008
Location: Pakistan
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Hi,
I need to increase the SGA of my oracle 10g(10.2.0.4) to 3Gb which is currently set to 1.15Gb. Please clarify, Is there any restriction on increasing SGA on Linux 5.3 32-bit Architecture? If Yes, Then to what maximum value we can set the SGA? Below is Os details.
>cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.3 (Tikanga)
>uname -r
2.6.18-128.el5PAE
> uname -a
Linux 2.6.18-128.el5PAE #1 SMP Wed Jan 21 08:28:30 EST 2009 i686 i686 i386 GNU/Linux
waiting for reply.
Thanks
[Updated on: Mon, 21 June 2010 05:11] Report message to a moderator |
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| Re: MAX SGA Limit on Linux 32-bit [message #461781 is a reply to message #461776] |
Mon, 21 June 2010 08:21  |
paradoxkhan
Messages: 92
Registered: April 2008
Location: Pakistan
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I have 8Gb Ram. It is planned to move to 64-bit in future. But as far need to go with the same. we are facing some db performance issues. ADDM and by seeing AWR we have planned to increase sga. I'm reviewing Link you have referred, But quick word, can i increase sga to 3Gb by seeing my box configuration?
Thanks
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| Re: MAX SGA Limit on Linux 32-bit [message #461805 is a reply to message #461781] |
Mon, 21 June 2010 10:50 |
mkounalis
Messages: 147
Registered: October 2009
Location: Dallas, TX
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paradoxkhan wrote on Mon, 21 June 2010 08:21
I have 8Gb Ram. It is planned to move to 64-bit in future. But as far need to go with the same. we are facing some db performance issues. ADDM and by seeing AWR we have planned to increase sga. I'm reviewing Link you have referred, But quick word, can i increase sga to 3Gb by seeing my box configuration?
Thanks
Short answer? No. Not even close. Again - 1.7 is pretty much the top end. The document describes how you can tweak various Linux kernel settings to allow you to move up over 2.5 (the article says 2.7 but I have never personally seen that . . . . ) but I have to say, it's a lot of work - and if this is a production system you are probably better off not fiddling with Linux kernel stuff as it takes a lot of reboot-iterations to nail down. If you have an exact mirror system for test/dev/qa then you might be able to tweak your kernel there and then mimic it in production . . . but again, it's a lot of work. There is a way to move the buffer cache into extended memory - but there are limitations for doing that. Remember - 32-bit means a max of 4gb of addressable memory. There is no magic to get around this - just some smoke and mirrors to band-aid it. A process needs to map in the Linux kernel memory structures to be able to talk to the various I/O devices you have configured - and by the way you are also going to be dealing with the low_mem 32-bit Linux kernel issue as well if you try and get the SGA up past 1.7 gb.
Good luck!
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| Re: MAX SGA Limit on Linux 32-bit [message #462279 is a reply to message #461805] |
Wed, 23 June 2010 06:19 |
paradoxkhan
Messages: 92
Registered: April 2008
Location: Pakistan
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Member |
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Ok thanks. we are going on 64bit system from 32-bit. Need to clear one thing.
we are going to take full expdp from current 32bit with user system and then after preparing 64bit box
we will import it there.
If we import full database all the users will be created automatically? no need to create users, only tablespaces needed to create before dpimport?
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