Server Administration

Question

Server Administration

Viewing 9 posts - 16 through 23 (of 23 total)

You must be logged in to reply to this topic. Login to reply

Robert Frasca SSCertifiable Points: 6026 More actions · Answer 1

Did you read the blog post from the CSS SQL Server group engineers? The AWE switch is NOT ignored and it is recommended as a best practice. Here is a snippet from the blog post:

So, the purpose of AWE for 32bit systems was to access more memory. But for 64bit, AWE APIs are used to avoid a working set trim. So SQL Server will automatically use the AWE APIs provided the 'lock pages in memory' privilege is set (and your are using Enterprise Edition). If you want to read more about the AWE APIs, look here in MSDN: http://msdn2.microsoft.com/en-us/library/aa366527.aspx

"Beliefs" get in the way of learning.

Cliff Jones SSChampion Points: 10547 More actions · Answer 2

Yes I did. Apparently I do not interpret it the same way that you do. I took the following to mean that you did not need to enable AWE to use the AWE API's on 64 Bit. We do not do this with our 64 bit servers. We were able to prevent the working set from being trimmed by merely locking pages in memory (in addition to setting Min/Max Memory properly).

For 64bit systems, the virtual address space limitation is not an issue. However, if an application wants to "lock its memory" or avoid its working set from being trimmed, then it can achieve this by using the AWE APIs. Again, in order to use these APIs, you must have the 'lock pages in memory' privilege set. This is why for 64bit systems, you don't need to set the 'awe enabled' option to 1 (it is actually ignored on 64bit systems).

Tom Garth SSCertifiable Points: 6193 More actions · Answer 3

I never gave a thought to 64 bit Windows/SQL Servers having different built in memory allocation settings than the 32 bit versions.

In fact, I figured that Windows Server 2008 wouldn't need an adjustment in 64 or 32, but I've olny dealt with the 64 bit version so far.

Thanks for the question.

Tom Garth
Vertical Solutions[/url]

"There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves." -- Will Rogers

Robert Frasca SSCertifiable Points: 6026 More actions · Answer 4

Cliff Jones (1/11/2010)
Again, in order to use these APIs, you must have the 'lock pages in memory' privilege set. This is why for 64bit systems, you don't need to set the 'awe enabled' option to 1 (it is actually ignored on 64bit systems).

Perhaps we're having a semantic argument. There are a number of articles around that explain how 64-bit memory management works with the AWE Enabled option set. In fact, if you've turned on 'lock pages in memory' I believe you'll find that the AWE Enabled box is checked whether you like it or not; however, if you don't have "lock pages in memory" set then you can't set the AWE enabled switch. The overriding point is that AWE functionality is used on 64-bit machines. It isn't just a 32-bit feature. The difference is that the functionality provides a different set of benefits in a 64-bit environment.

"Beliefs" get in the way of learning.

Cliff Jones SSChampion Points: 10547 More actions · Answer 5

Robert Frasca (1/11/2010)
Cliff Jones (1/11/2010)
Again, in order to use these APIs, you must have the 'lock pages in memory' privilege set. This is why for 64bit systems, you don't need to set the 'awe enabled' option to 1 (it is actually ignored on 64bit systems).
Perhaps we're having a semantic argument. There are a number of articles around that explain how 64-bit memory management works with the AWE Enabled option set. In fact, if you've turned on 'lock pages in memory' I believe you'll find that the AWE Enabled box is checked whether you like it or not; however, if you don't have "lock pages in memory" set then you can't set the AWE enabled switch. The overriding point is that AWE functionality is used on 64-bit machines. It isn't just a 32-bit feature. The difference is that the functionality provides a different set of benefits in a 64-bit environment.

I was not aware of that, point taken. I agree the question was lacking. I think what people should take away from this is that you want to get the memory settings on 64 bit correct; set Min/Max memory, and lock pages in memory. If the working set gets trimmed, performance is in the toilet.

Robert Frasca SSCertifiable Points: 6026 More actions · Answer 6

I think what people should take away from this is that you want to get the memory settings on 64 bit correct; set Min/Max memory, and lock pages in memory. If the working set gets trimmed, performance is in the toilet.

Succinctly accurate.

"Beliefs" get in the way of learning.

Scott Coleman One Orange Chip Points: 27452 More actions · Answer 7

I've whined about misleading questions in the past, but this one seemed perfectly clear. It asked what was the best option to allocate maximum available RAM to SQL Server 64-bit. If you do nothing then it will grab all the memory it can.

This may be the wrong configuration for most servers in the real world, but the answer is not wrong. The question contained a very precise and unambiguous definition of what was meant by "best".

Robert Frasca SSCertifiable Points: 6026 More actions · Answer 8

That'll teach me to read the question a little more carefully. Of course, then we couldn't have had a fascinating discussion on AWE and Lock Pages in memory. 🙂

"Beliefs" get in the way of learning.

Swarndeep SSCrazy Points: 2347 More actions · Answer 9

Thanks Scott.

Swarndeep

http://talksql.blogspot.com