Re: How to correctly use /PAE and AWE

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Date: Sat, 10 Jul 2004 08:16:39 -0700

Hi Andy

AWE is physical memory too! The /3gb switch gives you access to another GB
of ADDRESS SPACE, so you can directly address more memory instead of going
through the AWE maps. Direct address is always faster than going through the
mapping. (But, as you said, the most important reason for /3gb is that only
the buffer pool (hashed data and index pages) can use the AWE memory. )

--
HTH
----------------
Kalen Delaney
SQL Server MVP
www.SolidQualityLearning.com
"Andrew J. Kelly" <sqlmvpnooospam@shadhawk.com> wrote in message
news:eoLOOZfZEHA.2340@TK2MSFTNGP09.phx.gbl...
> The /3GB gives SQL Server access to an extra GB of physical memory vs AWE
> memory.  There only part of SQL Server that can use > 4GB of ram is the
data
> buffer pool. Every thing else lives in < 4GB.  So you get an extra GB of
> comfort if you need it for these other areas of memory.  I don't think it
> matters which is first in the Boot.ini.
>
> --
> Andrew J. Kelly  SQL MVP
>
>
> "Jerrick D.H" <Jerrick D.H@discussions.microsoft.com> wrote in message
> news:4A31A8B6-6B3E-4190-970B-0E4FCBA5ACE3@microsoft.com...
> > Andrew,
> > Thank you for the info. What is the reason for recommending the use of
the
> 3GB switch?
> > I thought that by enabling AWE and setting both the Min and Max Memory
SQL
> Server would ignore the 3GB switch. In the Bootini would this be added
> before or aftere /PAE?
> > With AWE enabled is the use of the paging file negated?
> >
> > Desiree
> >
> > "Andrew J. Kelly" wrote:
> >
> > > > We upgraded the 2 servers in the cluster from 4GB to 11GB Ram each
and
> > > would like to enable AWE .
> > > > 1. Based on my reading I would also have to set Max Server Memory
and
> > > Set Working Size configuration options how would >I determine
> appropriate
> > > values for these options?
> > >
> > > Yes you need to set the Max Memory setting to something less than the
> max.
> > > If SQL Server is the only thing running you might want to try 10GB and
> see
> > > how that works out.   Do NOT set the Set working set size.  AWE
> essentially
> > > does this by itself and that is why it is critical to leave memory for
> the
> > > OS.
> > >
> > > > 2. Are they other options that I need to be concerned with?
> > >
> > > You probably want to set the /3GB switch in the Boot.ini file as well.
> > >
> > > > 3.  Other than starving the OS what else can be affected by this
> change?
> > >
> > > As long as there are not other apps runing on this that is mostly it.
> > >
> > > > 4. Are there any other default settings that have to be changed?
> > > No, but make sure you do this on both the Active and Passvie nodes.
> > >
> > >
> > > --
> > > Andrew J. Kelly  SQL MVP
> > >
> > >
> > > "Jerrick D.H" <Jerrick D.H@discussions.microsoft.com> wrote in message
> > > news:5DCC1564-9608-4283-ABF8-3A12AD298417@microsoft.com...
> > > > Setup:
> > > > OS: Windows 2000 Advance Server
> > > > SQL Server 2000 Enterprise Edition service pack 3a - 1 instance
> > > > Ram upgraded from 4GB to 11GB
> > > > /PAE switch added to Bootini
> > > > SQL Server configuration settings - default
> > > > CPU 4 x 1.4
> > > > Cluster Active passive
> > > >
> > > > We upgraded the 2 servers in the cluster from 4GB to 11GB Ram each
and
> > > would like to enable AWE .
> > > > 1. Based on my reading I would also have to set Max Server Memory
and
> > > Set Working Size configuration options how would I determine
appropriate
> > > values for these options?
> > > > 2. Are they other options that I need to be concerned with?
> > > > 3.  Other than starving the OS what else can be affected by this
> change?
> > > > 4. Are there any other default settings that have to be changed?
> > > >
> > > > SQL Server is the primary application running on the cluster. There
> are no
> > > applications compiled to use 3GB memory.
> > > >
> > >
> > >
> > >
>
>

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