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7 Replies Last post: Sep 30, 2009 6:41 PM by avasudevan  

VM with W2003 64bits & 4GB of RAM showing less (3.75GB) posted: Jul 2, 2009 11:10 AM

Click to view RaMorn's profile Novice
RaMorn
6 posts since
Nov 5, 2008

Hi Folks,
I'm having the following question for you guys...

I had installed a VM with Windows Server 2003 Standard 64 bits, and I assigned to the VM 4GB.

But when it finished the installation it is showing 3.75 Gb....I was digging into the webpages, but it not seems to be related to software (I mean, I didn't find something like a switch to add to boot.ini file or something like this)

Has anyone experienced the same?

The ESX server where it is hosted is a HP Proliant G5 580 Intel.

I'll really appreciate your comments regarding this issue, I need to send official excuses if this could not be addressed.

Thanks!

Raul

Tags: vm, 2003, 64bits, less, memory, than, installed

Re: VM with W2003 64bits & 4GB of RAM showing less (3.75GB)

1. Jul 2, 2009 11:26 AM in response to: RaMorn
Click to view danpalacios's profile Hot Shot
danpalacios
126 posts since
May 14, 2007

That is odd. I would expect that behavior from a 32 bit version .. are you sure it installed as x64? What version of esx are you on?

Another interesting test would be to increase the RAM to 5 GB and see if any more shows up. If you are loosing a fraction of RAM would be a different issue than if you are capped at 3.75

Re: VM with W2003 64bits & 4GB of RAM showing less (3.75GB)

2. Jul 2, 2009 11:27 AM in response to: RaMorn
Click to view bjmoore's profile Hot Shot
bjmoore
101 posts since
Mar 9, 2007
Try adding the /pae switch to the boot.ini string. I've run into that problem on a lot of Standard edition servers before...not sure if it's resolved with 64-bit OS's.

Re: VM with W2003 64bits & 4GB of RAM showing less (3.75GB)

3. Jul 2, 2009 12:49 PM in response to: danpalacios
Click to view RaMorn's profile Novice
RaMorn
6 posts since
Nov 5, 2008

Yeah, I'm absolutely sure that was installed an x64 version, also during the VM creation, the appropiate OS version was selected, and the ESX host has enabled the VT and EM64T features...

Any thoughts?

Re: VM with W2003 64bits & 4GB of RAM showing less (3.75GB)

4. Jul 2, 2009 12:51 PM in response to: RaMorn
Click to view danpalacios's profile Hot Shot
danpalacios
126 posts since
May 14, 2007
I would love to know if more RAM shows up if you add more RAM to the VM. Try giving it 5 GB and see what the vm shows.

Re: VM with W2003 64bits & 4GB of RAM showing less (3.75GB)

5. Jul 3, 2009 11:37 AM in response to: danpalacios
Click to view RaMorn's profile Novice
RaMorn
6 posts since
Nov 5, 2008

Well, I'm back with my testings...

What I found is that if I add more memory (I tested with 5 and with 8 GB) it is always taking 256 MB for something...

Is there any official document indicating this case?

Thansk for your comments!

Re: VM with W2003 64bits & 4GB of RAM showing less (3.75GB)

6. Sep 29, 2009 2:07 AM in response to: RaMorn
Click to view Sav2k's profile Lurker
Sav2k
1 posts since
Sep 29, 2009

We are having the same issue. This is only happening on ESX 3.5 with WK23 x64. We have a vSphere on similar hardware to yours and this works correctly showing the full 4 GB.

Does anyone know any more on this?

Re: VM with W2003 64bits & 4GB of RAM showing less (3.75GB)

7. Sep 30, 2009 6:41 PM in response to: Sav2k
Click to view avasudevan's profile Lurker
avasudevan
1 posts since
Sep 30, 2009

This is most likely due to RAM reservation for virtual PCI devices. PCI devices need memory for their IO and those pages are not available to the OS. Hence the gap that you see...

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