W2K8 Guest Memory displays Maxed out Threashhold in ESX 4.0, OS is not though?

[peacey]

Alreet guys,

I have A little Resource Management thing going on which I am now Stuck

with.

We have a new vSphere (6 ESX 4.0 Hosts / 1 Single vCenter server)

estate which we are using with mostly W2K8 32Bit Standard servers running

AD/Citrix/File and Print/Apps/DB/Vcetner. On some (Not all) servers ESX and VC

start reporting that the Guest memory usage is @ 99/100% constantly which is

alarming all day and all night back to our monitoring system. the thing is it's

reporting this on servers which are only using between (Within the OS) 30-40

percent of allocated memory to that guest.

Have a look at the attachment for one of our Domain Controllers (W2K8) which

is doing nothing at present. yet we have a second DC (from the same template

and configured in exactly the same way) that reports correctly. Can anybody

help?

I have played and tinkered with advanced 'mem' configuration and VM MMU

which I was reading up on and though I had solved this but the memory

utilisation counters have just gone back to 100%.......

Using Dell Blade M610, 2 X Quad E5570 I7 Intel CPU's, 32GB Ram

Regards

Peacey

[bulletprooffool]

It could be that you have over allocated memory to your VMs - they are running and have memory available from within the OS, but in the mean time the hosts are are shifting all the memory pages out to vswp (which the OS does not know about), because you do not have enough physical memory?

What is the total memory allocated to your VMs on each host - how much physical memory is installed?

[bulletprooffool]

Also, if you have the VMTools installed, there are better counters to monitor . . open perfmon and use the VMMemory counters to try track down what is actually being used.

And lastly, the memory percentage being showed is as a total of the combined physical memory AND page file assigned to the VM.

[peacey]

Hi Bulletprooffool

This is not the case as the ESX Guests are only about 40% utilised memory wise. For example we have 4 virtual machines running on ESX1, 2VM's configured with 2GB and 2 Vm's with 4GB thats a total of 12GB of memory allocated to the VM guests the Blade has 32GB of physical memory so there would be a minimal amout od Vswap going on surley.

Regards

Peacey

[peacey]

Ok Thanks, I will look into the Perfmon counters. Any idea these counters display as availble counters in W2k3 and not W2K8, my issue is just with 2008 server not 2003. all my 2003 servers accross all esx hosts are running as they should be.

Regards

Peacey

[bulletprooffool]

peacey - if the VMtools are installed, the counters should be available (this is really just to demonstrate what you are actually using)

Also, try get on the ESX host's comman console and use esxtop, to see what the VMs are actually doing.

If you have verified that the guests ARE using nearly all their memory, we will need to start looking at how / where, but of course this is difficult of your OS only returns 30%

[monkeh99]

Server 2008 memory management is totally different from Server2003. It will take all remaining memory and use it for cache to speed up operations, as soon as a program is loaded it takes the memory out of the cache.

The %physical memory figure is used to should how much of the physical memory is used for anything other the cache. I have not found any way to limit the meory that windows takes for the cache!

[bulletprooffool]

Peacey - check that you have not set reservations / limits for these VMs and that any resource pools that they live in are not oversubscribed!

If you have to, remove all these settings on one of the VMs and move it out of any resource pools - see if this makes a difference?

[peacey]

There are no Resource pools or VM Resource limits on any of the VM's.

Regards

Peacey

[bulletprooffool]

Is the problem the same for all VMs on each ESX host, or is it not bound to ESX hosts?

[bulletprooffool · Accepted solution]

http://communities.vmware.com/thread/226513?tstart=0 ?

[peacey]

Nice one Bulletprooffool, and as if by magic.............................

Regards

Peacey