Cannot use Large Page Extensions & AWE

Hi,

We are seeing the following line on the sql errorlog on a Itanium2 server running SQL Server 2005 Enterprise RC1.

Cannot use Large Page Extensions: lock memory privilege was not granted.

Is it something to be alarmed with?

This server has 16GB memory so it's my understaning that AWE does not have to be enabled on the instance as the 64-bit architecture can directly address more than 3GB of memory?
Cheers,
Priyanga

Few questions:

(1) Have you enabled AWE option. Assume not, but checking.
(2) Are you running 32-bit version of SQL Server on a 64-bit machine? 32-bit windows applications automatically run on 64-windows through WoW.
(3) Are you starting SQL Server with any trace flags?

|||

Short answer to your question, no, you don’t have to worry, but read on.

Indeed 64-bit SQL Server can address more than “usual” limit of 32 bit address space.

However, locked pages in memory privilege allows SQL Server to keep pages in memory and do not allow the OS to page them out. This may translate to performance gain, but does require the privilege. The privilege also allows to use large page extensions, which also may be benefitial for performance reasons.

You will get this message in default server configuration if you have large amounts of RAM (which you do).

I would recommend enabling the privilege and testing your server. You may get performance gain.

HTH,
Boris.

|||

Thanks Boris.

How do i enable the "locked pages in memory privilege" setting?
I could not see this as a sql server system configuration.

Also, to clarify, i don't need to enable "AWE enabled" configuraton on this instance as 64-bit does it natively?

Cheers,
Priyanga

|||

It is Windows level privilege. This is from Windows help:

You can configure this security setting by opening the appropriate policy and expanding the console tree as such: Computer Configuration\Windows Settings\Security Settings\Local Policies\User Rights Assignment\.

This security setting determines which accounts can use a process to keep data in physical memory, which prevents the system from paging the data to virtual memory on disk. Exercising this privilege could significantly affect system performance by decreasing the amount of available random access memory (RAM).

I would like to emphasize the last point. Understand the implication of granting this privilege. E.g. if you have something else on this server, SQL Server may effectively consume most of the RAM, unless you set 'max server memory' as well. This is why I recommend testing your server.

As for the second quesiton, no, you do not need to set "AWE enabled" on 64-bit server.

Regards,
Boris.