Virtual Center reading Memory usage for VM incorrectly.

[Addammer]

ESX 3.5

vCenter 2.5

Windows Server 2008 x64

I have vCenter configured to alarm us when memory usage raises above 80%. One particular Windows server is repeatedly showing high memory usage inside vCenter, however when I check Task Manager on the machine itself the memory usage is operating normally. If I reboot the server and check the performance monitor inside vCenter everything reads ok and low. If I do not touch the server for 4 days the memory will stay low. As soon as I log into the server and start configuring and changing options the memory usage inside vCenter grows quickly and eventually will start alarming us (once again, task manager on the machine is not telling me what vCenter is telling me). The only way to make it stop is restart the machine.

Is vCenter not reading the release of the memory?

I've tried bumping the memory to 6Gb and that did not help at all. Same symptom, and I can't see any way that i'd be using 6Gb of memory.

Thank you,

[dnetz]

What update version of ESX 3.5 are you running and what Windows 2008 service pack? It seems Service Pack 1 is supported from ESX 3.5 U2 and Service Pack 2 from ESX 3.5 U4. Are you running the latest vmware tools on the machine?

Remember that newly booted Windows VM's tend to warn on high memory usage due to Windows zeroing all pages but this should disappear after a few minutes.

[hamilton00]

Does the VM have a memory limit set? I believe I've seen this in the past where if you allocate for example 4GB of memory but then set a memory limit of say 1GB.

[Addammer]

Running ESX 3.5 Update 4 on both ESX servers.

I'm going to move the problem VM over to a different ESX server as my next step in debugging.

at 10:30 last night I started a full backup of this vm. Soon after that we started recieving alarms about low memory. This morning I logged into the server and found Task Manager to be reading at a low level. Virtual Center is NOT reading the memory usage correctly and has been nearly pegged since 10:35 last night.

[Addammer]

I'm still having a problem with this.

I rebooted the server and haven't logged in for 3 days which means no alarms!

Still curious...Were their any additions/upgrades to the Alarm's in the new VirtualCenter?

[dnetz]

Not that I know of. Did you try hamilton00's suggestion and check for memory limits? If these are set below the machine memory setting then you might get weird/slow behaviour from the VM when it tries to use more memory than ESX will let it.

[Addammer]

Where do you set the Memory limits?

i have allocated 3Gb.

[dnetz]

In the virtual machine properties, resources tab, memory setting. The checkbox for unlimited should be checked or the limit value higher than 3 GB. If the virtual machine is part of a resource pool, then check the same setting for the pool as well.