How to limit the number of processor SQL servur uses.

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How to limit the number of processor SQL servur uses.

egpotus

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March 30, 2009 at 3:18 am

#384243

Hi,
Is it possible to tell SQL server to use only 4 processors out of 8 ?
I would like to dedicate 1 SQL server instance to processor 0 to 3 and a Second SQL server instance to processor 4 to 7, is it possible?
Can I use affinity mask Option ?
regards
Kindest Regards,
egpotus DBA

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David Sorauer SSCrazy Points: 2874 More actions · Answer 1

You can use Affinity mask. From my experience, SQL Server performed better when i left SQL Server to automatically set the affinity...

egpotus SSCommitted Points: 1654 More actions · Answer 2

I have one server with 8 CPU (CPU0, CPU1... CPU7) , I am using 2005 Standard Sql version so I am limited to 4 CPU.

I have 2 instances running on my server, how can I tell one instance, using affinity mask, to only use CPU4 to CPU7?

Kindest Regards,

egpotus DBA

Grant Fritchey SSC Guru Points: 398882 More actions · Answer 3

Just open up the Server Properties in SSMS. On the Processors page you can see how many processors you have available and set them to a particular affinity. I'd suggest reading up in the BOL prior to setting it, just so you get it right.

"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt

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SQL Server Query Performance Tuning

egpotus SSCommitted Points: 1654 More actions · Answer 4

Those parameters cannot be update using SSMS, do you know why ?

Kindest Regards,

egpotus DBA

Grant Fritchey SSC Guru Points: 398882 More actions · Answer 5

First disable the automatic affinity in the check box below.

"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt

Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning

Jeffrey Williams SSC Guru Points: 90303 More actions · Answer 6

BTW - when they say SQL Server can only use 4 CPU's - they are talking about slots. A single quad core processor is one CPU's as far as licensing and utilization. So, SQL Server Standard can use up to 16 CPU's if you use 4 quad-core processors.

Jeffrey Williams
“We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

― Charles R. Swindoll

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egpotus SSCommitted Points: 1654 More actions · Answer 7

thank you for this help

Kindest Regards,

egpotus DBA

Welsh Corgi SSC Guru Points: 116520 More actions · Answer 8

Since moving two Databases and several SSIS Packages I'm having issues with the AS400 iSeries and I'm getting Communication errors.

Several task fail. It seems that the task complete much faster and as if the AS400 can't keep up with it.

Should I limit the number of processors?

If I limit the number of parallel loads, SSIS Tasks, I have been able to avoid the error.

I have 1 64 bit Windows Server 2008 R2 running SQL Server 2008 R2.

I looked it up on BOL but I have never had to mess with changing the number of processors.

Any ideas would be greatly appreciated.

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