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Windows 2003 Enterprise 32bit VM RAM can't go beyond 4GB & increasing vCPU slows VM

Posted on 2013-06-21
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Last Modified: 2013-06-22
We have P2V'ed a Win2003 SP2 that run SQL 2005 to VM &
then run some batch jobs (SQL & Stored Procedures) that we
previously ran in the physical servers with same parameters
as what they used to run while on physical server for
comparison purpose to see if performance improves.

The SAN LUN which hold the DB is presented over to the
VM so that the P2V'ed VM can access it as RDM.  Results of
the test showed it takes about the same amt of time.

Thereafter we shut down the VM, did 'Edit Settings" &

a) double the number of cores (to double the vCPU )

b) double the RAM to 8GB

After bootup, we noted under Computer Properties, the
# vCPU did double but the RAM stays at 4GB.


Q1:
We did enable PAE on the Win 2003 but why is it the amt
of RAM did not reflect as 8GB?  I can send you a screen
shot of the PAE setting if needed.

The link below indicates that with /PAE, it's suppose to be
able to go up to 64GB.


Q2:
We then reran exactly the same stored procedure & SQL
jobs (with exact same parameters) but this time, it took
5-30% longer with one of the job giving the same amt
of timing.  What could be the reason.  The peak CPU for
this VM was 17% only while the jobs are being run as we
used Performance Chart to monitor while it's being run.
I read that increasing vCPU could be bad for performance
in some cases (in one past EE thread that I saw) : under
what circumstances will it be slower?
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Question by:sunhux
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3 Comments
 
LVL 118

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by:Andrew Hancock (VMware vExpert / EE MVE)
Andrew Hancock (VMware vExpert / EE MVE) earned 490 total points
ID: 39265811
Q1. Windows Server 2003, Enterprise Edition maximum limit is 64 GB, this assumes Limits over 4 GB for 32-bit Windows assume that PAE is enabled.

see here

http://msdn.microsoft.com/en-us/library/windows/desktop/aa366778%28v=vs.85%29.aspx#physical_memory_limits_windows_server_2003

Q2. It is also true, that additional vCPUs can slow a virtual machine down, if the application does not support multiple CPUs e.g. vSMP.

We have also seen, SQL server performance dip, and get worse, when they have been moved to a hypervisor. We spend alot of our time performing V2P moving virtual servers to physical servers, because SQL can perform poorly on a hypervisor.
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Author Comment

by:sunhux
ID: 39266349
Ok, I've just got the operator to send me the boot.ini of this
Win 2003 Standard (sorry, I made a mistake to say it's Win2003
Enterprise earlier, but it's actually Standard edition) :

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows Server 2003, Standard" /fastdetect /NoExecute=OptOut / PAE /3GB

So what's wrong with the above boot.ini ? Is it due to /NoExecute=OptOut
and the /3GB switches that stops the VM from recognizing the additional
RAM granted?
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LVL 118

Accepted Solution

by:
Andrew Hancock (VMware vExpert / EE MVE) earned 490 total points
ID: 39266621
Windows Server 2003, Standard Edition the maximum is 4 GB!

This is to be expected upgrade the version from Standard to Enterprise.
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