Memory Configuration and /3GB /PAE Switches

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Memory Configuration and /3GB /PAE Switches

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sqldba20

Posted Friday, July 25, 2008 8:41 AM

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All:

We have a new Windows server and are working on configuring the memory. Read a lot about /3GB , /PAE , AWE and got a little bit confused so thought I will post it here and see what do you folks thinks how I am going to configure?

Our New Windows Environment.

Windows 2003 Enterprise Edition (32 bit)
Memory - 16 GB
SQL 2005 Enterprise Edition (32 bit)

I would like to give not more than 2 GB for the OS / Kernel (14 GB we want for SQL) and based on that here is what I am planning to configure. Let me know if I am right or wrong?

On Windows Enable the /3GB /PAE switch
On SQL Server Enable AWE and set the MAx Server Memory to 14 GB

Thanks !

Post #540972

jason.stephens

Posted Friday, July 25, 2008 9:15 AM

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That is what we did but we capped ours at 12 GB. It showed incredible gains in efficiency.

Edit: ours was only SQL 2000 that we did this on.

Post #541013

Perry Whittle

Posted Friday, July 25, 2008 10:01 AM

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ensure you configure the "lock pages in memory" local security policy for the account SQL runs under. Generally its not recommended to use the /3GB switch for machines with 16GB RAM and over. Using the /3GB switch with machines using large amounts of RAM (reportedly 12GB and over) can effect the way the machine addresses the memory

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Post #541088

sqldba20

Posted Friday, July 25, 2008 11:00 AM

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So only Enabling /PAE should also help.., right?

Post #541160

jason.stephens

Posted Friday, July 25, 2008 11:20 AM

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Milton Gonsalves (7/25/2008)

So only Enabling /PAE should also help.., right?

Not from what I have read. PAE just lets windows utilize all the memory. AWE has to be turned on in SQL for SQL to be able to use more.

Edit: We didn't see the performance increase until we turned on AWE in SQL.

Post #541184

Perry Whittle

Posted Monday, July 28, 2008 6:30 AM

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Milton Gonsalves (7/25/2008)

So only Enabling /PAE should also help.., right?

if your using win 2003 enterprise it should address all the RAM straight off without editing the boot.ini

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Post #541824

jim.powers

Posted Monday, July 28, 2008 11:16 AM

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Perry Whittle (7/28/2008)

Milton Gonsalves (7/25/2008)

So only Enabling /PAE should also help.., right?

if your using win 2003 enterprise it should address all the RAM straight off without editing the boot.ini

When installing Win 2003 Enterprise (32-bit), it will automatically recognize the need for the /PAE switch and should add it automatically to the boot.ini. If that switch is not already there, it does need to be added. Win 2003 64-bit does not require the /PAE switch, 32-bit does.

Post #542067

Perry Whittle

Posted Monday, July 28, 2008 12:53 PM

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jim.powers (7/28/2008)

If that switch is not already there, it does need to be added.

on the very rare odd occasion and normally for older processor architecture. 99% of the time the processor architecture will automatically configure the boot.ini at install time with the DEP option /noexecute. This switch implies and automatically switches on /PAE

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Post #542129

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