Saturday, February 25, 2012

AWE

Our current production environment consists of an 2 node (active-active) SQL
Server 2000 SP3a database cluster. It was recently rebuilt and we did not
reenable Address Windowing Extensions (AWE). Is it recommended that I turn
it on? Both servers have 8 procs running at 2.8 Ghz and 8 GB of RAM. I am
asking this because it appears to be performing well with AWE off. Also
should I allocate 7 GB of RAM to for 'max server memory'? It is not set now,
but is performing well without it.
Thanks,
Jay
Hi,
If you have 8 GB ram please enable AWE. My value for SQL Server will be from
6 to 6.5 GB.
I will leave the rest to OS and other applications.
Thanks
Hari
SQL Server MVP
"jay d" <jayd@.discussions.microsoft.com> wrote in message
news:2B3700C8-036C-454E-A50A-D156CBA98EAC@.microsoft.com...
> Our current production environment consists of an 2 node (active-active)
> SQL
> Server 2000 SP3a database cluster. It was recently rebuilt and we did not
> reenable Address Windowing Extensions (AWE). Is it recommended that I
> turn
> it on? Both servers have 8 procs running at 2.8 Ghz and 8 GB of RAM. I
> am
> asking this because it appears to be performing well with AWE off. Also
> should I allocate 7 GB of RAM to for 'max server memory'? It is not set
> now,
> but is performing well without it.
> Thanks,
> Jay
|||"jay d" wrote:
> Our current production environment consists of an 2 node (active-active) SQL
> Server 2000 SP3a database cluster. It was recently rebuilt and we did not
> reenable Address Windowing Extensions (AWE). Is it recommended that I turn
> it on? Both servers have 8 procs running at 2.8 Ghz and 8 GB of RAM. I am
> asking this because it appears to be performing well with AWE off. Also
> should I allocate 7 GB of RAM to for 'max server memory'? It is not set now,
> but is performing well without it.
Jay,
If the servers are running well without AWE, I would say keep it turned
off.
In my experience, the AWE implementation has some bugs. Better to keep
it simple unless you need the extra memory.
-- J
|||Just because you have lots of ram does not mean sql server will be able to
use it all effectively. It depends a lot on your data and how you access it.
If your cache hit ratio and page life expectancy arealways high and your
response times are good you may not need to turn it on. But if you do you
certainly should not set it to 7gb since you have an active - active
configuration. Since AWE memory is not dynamic you can have a situation
where one instance gets 7GB and leaves only 1GB for the other instance and
the OS and performance will suffer on all fronts.
Andrew J. Kelly SQL MVP
"jay d" <jayd@.discussions.microsoft.com> wrote in message
news:2B3700C8-036C-454E-A50A-D156CBA98EAC@.microsoft.com...
> Our current production environment consists of an 2 node (active-active)
> SQL
> Server 2000 SP3a database cluster. It was recently rebuilt and we did not
> reenable Address Windowing Extensions (AWE). Is it recommended that I
> turn
> it on? Both servers have 8 procs running at 2.8 Ghz and 8 GB of RAM. I
> am
> asking this because it appears to be performing well with AWE off. Also
> should I allocate 7 GB of RAM to for 'max server memory'? It is not set
> now,
> but is performing well without it.
> Thanks,
> Jay
|||Thank you all for the help. One more quick question. If I am 3 instances
should I set the max server memory to 7 GIG on each of them or do I divide
the RAM among the 3 instances? ex Instance 1 - 3 GIG, Instance 2 - 3 GIG,
and Instance 3 - 2 GIG.
Thanks,
Jay
"Andrew J. Kelly" wrote:

> Just because you have lots of ram does not mean sql server will be able to
> use it all effectively. It depends a lot on your data and how you access it.
> If your cache hit ratio and page life expectancy arealways high and your
> response times are good you may not need to turn it on. But if you do you
> certainly should not set it to 7gb since you have an active - active
> configuration. Since AWE memory is not dynamic you can have a situation
> where one instance gets 7GB and leaves only 1GB for the other instance and
> the OS and performance will suffer on all fronts.
> --
> Andrew J. Kelly SQL MVP
>
> "jay d" <jayd@.discussions.microsoft.com> wrote in message
> news:2B3700C8-036C-454E-A50A-D156CBA98EAC@.microsoft.com...
>
>
|||As I stated when you set AWE it is no longer dynamic. The first instance to
come up will grab all the memory it can up to the MAX Memory setting. If
you set it to 7GB for each instance and you only have 8GB total there isn't
enough to go around. When you use AWE you can not share the memory. So if
you really do have three instances that is probably the real reason why AWE
is turned off to begin with.
Andrew J. Kelly SQL MVP
"jay d" <jayd@.discussions.microsoft.com> wrote in message
news:9144E391-55F4-4B7F-9858-321A6973AE50@.microsoft.com...[vbcol=seagreen]
> Thank you all for the help. One more quick question. If I am 3 instances
> should I set the max server memory to 7 GIG on each of them or do I divide
> the RAM among the 3 instances? ex Instance 1 - 3 GIG, Instance 2 - 3 GIG,
> and Instance 3 - 2 GIG.
> Thanks,
> Jay
> "Andrew J. Kelly" wrote:
|||Hi,
Thanks, I will enable AWE. If I have 2 instances of SQL running, should I
set each instance to 3 GIG RAM and then leave 2 GIG for the OS, just in case
one node of the cluster fails and both instances end up on the same node for
awhile?
Thanks,
Jay
"Hari Prasad" wrote:

> Hi,
> If you have 8 GB ram please enable AWE. My value for SQL Server will be from
> 6 to 6.5 GB.
> I will leave the rest to OS and other applications.
> Thanks
> Hari
> SQL Server MVP
> "jay d" <jayd@.discussions.microsoft.com> wrote in message
> news:2B3700C8-036C-454E-A50A-D156CBA98EAC@.microsoft.com...
>
>
|||Just be sure not to apply SP4 for SQL Server. There is a bug with respect
to AWE. They are working on a fix.
Tom
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
SQL Server MVP
Columnist, SQL Server Professional
Toronto, ON Canada
www.pinpub.com
..
"jay d" <jayd@.discussions.microsoft.com> wrote in message
news:8A900118-4F9B-4378-87F5-15EA79CC42F4@.microsoft.com...
Hi,
Thanks, I will enable AWE. If I have 2 instances of SQL running, should I
set each instance to 3 GIG RAM and then leave 2 GIG for the OS, just in case
one node of the cluster fails and both instances end up on the same node for
awhile?
Thanks,
Jay
"Hari Prasad" wrote:

> Hi,
> If you have 8 GB ram please enable AWE. My value for SQL Server will be
> from
> 6 to 6.5 GB.
> I will leave the rest to OS and other applications.
> Thanks
> Hari
> SQL Server MVP
> "jay d" <jayd@.discussions.microsoft.com> wrote in message
> news:2B3700C8-036C-454E-A50A-D156CBA98EAC@.microsoft.com...
>
>

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