Sunday, March 25, 2012

32 bit vs. 64 bit options

We are currently running 32 bit SQL Server 2005, Standard Edition, SP2, on
Windows 2003.
We have 8GB RAM, with AWE enabled, Lock Pages in Memory, /3GB switch, and Max
Server Memory set to 6144.
After a recent application upgrade, we were running into memory pressure due
to limited space in VAS. Our buffer pool remained in good shape. We increased
VAS from 256 to 512 and we are no longer having any issues.
During this troubleshooting period, we began toying with the idea of moving
from SQL Server 32 bit to 64 bit. We have a 64 bit test environment in the
process of being set up. With the same 8GB RAM on the proposed 64 bit server,
is it desirable to have the sp_Configure options in 32 bit (such as AWE, Max
Server Memory) remain the same in 64 bit? Is the /3GB switch still necessary?
What is the default size of VAS in 64 bit?
Message posted via droptable.com
http://www.droptable.com/Uwe/Forums.aspx/sql-server/200705/1
/3gb and AWE is no longer required with x64
max memory option still here.
Windows x64 is required.
and sure, x64 version is really helpful for the memory management.
"cbrichards via droptable.com" <u3288@.uwe> wrote in message
news:71d7704e288d2@.uwe...
> We are currently running 32 bit SQL Server 2005, Standard Edition, SP2, on
> Windows 2003.
> We have 8GB RAM, with AWE enabled, Lock Pages in Memory, /3GB switch, and
> Max
> Server Memory set to 6144.
> After a recent application upgrade, we were running into memory pressure
> due
> to limited space in VAS. Our buffer pool remained in good shape. We
> increased
> VAS from 256 to 512 and we are no longer having any issues.
> During this troubleshooting period, we began toying with the idea of
> moving
> from SQL Server 32 bit to 64 bit. We have a 64 bit test environment in the
> process of being set up. With the same 8GB RAM on the proposed 64 bit
> server,
> is it desirable to have the sp_Configure options in 32 bit (such as AWE,
> Max
> Server Memory) remain the same in 64 bit? Is the /3GB switch still
> necessary?
> What is the default size of VAS in 64 bit?
> --
> Message posted via droptable.com
> http://www.droptable.com/Uwe/Forums.aspx/sql-server/200705/1
>
|||> What is the default size of VAS in 64 bit?
The user mode addressable space is 8TB.
Linchi
"cbrichards via droptable.com" wrote:

> We are currently running 32 bit SQL Server 2005, Standard Edition, SP2, on
> Windows 2003.
> We have 8GB RAM, with AWE enabled, Lock Pages in Memory, /3GB switch, and Max
> Server Memory set to 6144.
> After a recent application upgrade, we were running into memory pressure due
> to limited space in VAS. Our buffer pool remained in good shape. We increased
> VAS from 256 to 512 and we are no longer having any issues.
> During this troubleshooting period, we began toying with the idea of moving
> from SQL Server 32 bit to 64 bit. We have a 64 bit test environment in the
> process of being set up. With the same 8GB RAM on the proposed 64 bit server,
> is it desirable to have the sp_Configure options in 32 bit (such as AWE, Max
> Server Memory) remain the same in 64 bit? Is the /3GB switch still necessary?
> What is the default size of VAS in 64 bit?
> --
> Message posted via droptable.com
> http://www.droptable.com/Uwe/Forums.aspx/sql-server/200705/1
>
|||If you were running into VAS issues you must be running apps other than SQL
Server on the same server. If this is the case you should always leave
enough free memory for those other apps. The problem with 32 bit and AWE is
that it is not dynamic so when the other app or the OS needs more than the
2GB left you are forced to page. With x64 bit it can be dynamic and there is
no need for AWE or /3GB. But that still won't get around the issue that you
probably need more memory for the other apps.
Andrew J. Kelly SQL MVP
"cbrichards via droptable.com" <u3288@.uwe> wrote in message
news:71d7704e288d2@.uwe...
> We are currently running 32 bit SQL Server 2005, Standard Edition, SP2, on
> Windows 2003.
> We have 8GB RAM, with AWE enabled, Lock Pages in Memory, /3GB switch, and
> Max
> Server Memory set to 6144.
> After a recent application upgrade, we were running into memory pressure
> due
> to limited space in VAS. Our buffer pool remained in good shape. We
> increased
> VAS from 256 to 512 and we are no longer having any issues.
> During this troubleshooting period, we began toying with the idea of
> moving
> from SQL Server 32 bit to 64 bit. We have a 64 bit test environment in the
> process of being set up. With the same 8GB RAM on the proposed 64 bit
> server,
> is it desirable to have the sp_Configure options in 32 bit (such as AWE,
> Max
> Server Memory) remain the same in 64 bit? Is the /3GB switch still
> necessary?
> What is the default size of VAS in 64 bit?
> --
> Message posted via droptable.com
> http://www.droptable.com/Uwe/Forums.aspx/sql-server/200705/1
>
|||You are correct Andrew, the VAS issues came into play when we deployed CLR.
To clarify my understanding then, with 64 bit, when I have 8GB RAM, and Max
Server Memory = 6144:
1. If CLR or OS needs more than the 2GB left, then if 64 bit is dynamic, does
it then borrow from the 6GB in the buffer pool?
2. Regarding the VAS issues, in 32 bit the resolution was to increase the
default MemToLeave from 256 to 512 using startup parameter -g. Is this
startup parameter still needed in 64 bit, or in other words, is 256 still the
default in 64 bit?
Andrew J. Kelly wrote:[vbcol=seagreen]
>If you were running into VAS issues you must be running apps other than SQL
>Server on the same server. If this is the case you should always leave
>enough free memory for those other apps. The problem with 32 bit and AWE is
>that it is not dynamic so when the other app or the OS needs more than the
>2GB left you are forced to page. With x64 bit it can be dynamic and there is
>no need for AWE or /3GB. But that still won't get around the issue that you
>probably need more memory for the other apps.
>[quoted text clipped - 19 lines]
Message posted via droptable.com
http://www.droptable.com/Uwe/Forums.aspx/sql-server/200705/1
|||OK you have VAS confused with MemToLeave. The - g option is for MemToLeave
and not VAS. MemToLeave is for allocations that require more than 8K of
contiguous memory. I can see where the CLR would require more MemToLeave
than the default.
See if this helps:
http://blogs.msdn.com/khen1234/archive/2005/10/12/480292.aspx
Andrew J. Kelly SQL MVP
"cbrichards via droptable.com" <u3288@.uwe> wrote in message
news:71e09d8645e08@.uwe...
> You are correct Andrew, the VAS issues came into play when we deployed
> CLR.
> To clarify my understanding then, with 64 bit, when I have 8GB RAM, and
> Max
> Server Memory = 6144:
> 1. If CLR or OS needs more than the 2GB left, then if 64 bit is dynamic,
> does
> it then borrow from the 6GB in the buffer pool?
> 2. Regarding the VAS issues, in 32 bit the resolution was to increase the
> default MemToLeave from 256 to 512 using startup parameter -g. Is this
> startup parameter still needed in 64 bit, or in other words, is 256 still
> the
> default in 64 bit?
> Andrew J. Kelly wrote:
> --
> Message posted via droptable.com
> http://www.droptable.com/Uwe/Forums.aspx/sql-server/200705/1
>
sql

No comments:

Post a Comment