Questions[awe](server)

We have a "SQLServer 2005 SP3 32bit Enterprise Edition" running on a 32 bit Windows 2003 32bit Enterprise Edition 12GB RAM with AWE enabled using RAID5(5 pysical disks).

We tuned AWE to enabled and restart sqlserver this afternoon after work, hope the performance will be better than old time.

But there is something that we are very confused.

On working days, SQLServer has a very bad performance. When we are looking for reasons, we check Windows Performance counter.

Avg. Disk Read Queue Lenght > 140
Avg. Disk Write Queue Length < 1
SQL Server Buffer Cache Hit Ratio > 96%
%Processor Time < 30%
SQL Server Total Server Memory < 1.8G

Obviously, without AWE enabled, SQL Server can use only less than 2G memory. My Question is:

1. why "SQL Server Total server Memory" is less than 2G?I think SQL Server will use all 2G process address space. Does this counter count anything out?
2. we known that sql server is sufferring lack of memory, but why "buffer hit ratio“ is as high as 96?

Any advice is welcomed!

The server is Windows Server 2003 SP2 (32-bit), running SQL Server 2005 SP3 (32-bit). I believe the server has 4 GB of physical RAM. The machine has crashed twice in the last week and it is a production machine. From what I understand, it has AWE enabled with a maximum memory limit of 6041 MB. I never heard of AWE, but I thought this was a little suspicious and suspected thrashing was the reason the machine crashed.

(FYI, AWE is enabled and the /3GB switch is present in the boot.ini file).

I devoted some time today to SQL Server's memory architecture, and I don't think I quite grasp the concept of AWE.

So, Address Windows Extension (AWE) is relative to physical memory, not virtual memory (paging). If the machine only has 4GB of physical RAM, how can it use more than that, if it's not touching the paging file?

Or, is the server not applying AWE correctly? That is, say I have 8 GB RAM, but Windows 2003 32-bit user space can only access 2 GB (3GB with the switch). But with AWE enabled (and page locking in memory checked), I can use an additional 4GB of RAM for SQL Server 2005 (32-bit), on top of the 4GB for Windows (3GB Windows user space + 1GB Windows kernel space), IF AND ONLY IF I have the physical RAM to support it.

I'm really confused and need some guidance with this matter. I'm trying to determine if I understand AWE, how it works, and if it's contributing to the machine crashing.

Thank you for any help.

Hi I have a Win 2K3 with 6 gigs of memory.

I had 3 gigs, and then added 3 more.

However Windows won't recognize more than 4 Gigs as its a 32 bits machine.

What do I have to do to make things work?

I've two sql instances and set SQL Maximum memory for them both as 2560, and clicked Enable AWE checkbox.

Is this enough? I've heard it's actually not, windows should recognize the memory first. How do I do that? Is Min Memory required to be more than 0 for AWE to work?

Thanks in advance. Gabriel Guimarães

We have an SBS server running SQL Server 2005 and Exchange, that is notoriously tight on memory. (It's a battle between the sql and exchange).

It's not the time yet to replace it completely, but I wonder if stocking up to 8GB (the maximum the board supports, it currently holds 4GB) would help.

Since it's a 32 bit OS, the additional memory would be visible through AWE only, which at least SQL Server seems to support.

• Can I expect improvements?
• What config changes (Windows, SQL Server) are necessary so it makes use of AWE?
• Can Exchange benefit from the additional memory, too?

we have SQL Server installed on a Windows Server 2003 with 2GB of memory. Would it help if we enabled AWE? Or do we have to add more memory and then enable AWE?

Thanks