Windows Guest OS storage usage is different when they are powered on or powered off ?

[tamuxu]

We use vSphere 4.1.

We use thin provisioning for Windows Guest OS.

Windows Guest OS storage usage is different when they are powered on or powered off ?

[npadmani]

I think you are talking about VM storage utilization statistics.

It's all about how much VM consumes from the datastore.

Let's say I have a VM with 1 GB RAM allocation, when I power it on, it will create 1 GB vswp file in datastore. (I am not too sure if vSphere 4 shows your vmkernel overhead related vswp utilisation.)

which is actual utilization of your datastore space by that VM while powered-on on top of your vDisk utilisation (Thick/thin)

when you turn your VM off, utilisation of datastore goes down because vswp file gets erased at that time.

[tamuxu]

Thank you.

You mean that the difference is swap file data usage ?

[npadmani]

yes, in the VM storage utilisation stats, the additional usage you see is from vswp file related utilisation which comes into picture when VM is on.

I would also recommend exploring VM snapshots. because when VM has snapshots, that's when you see vm storage utilization stats go higher.