Question re VM disk usage on a VSAN datastore

[tekhie999]

Morning all - wonder if you can help me get an understanding of the provisioned and usage figures being shown on our VSAN clusters. The VSAN cluster is hybrid mode, and FTT=1

I have a windows VM with a thin provisioned vmdk

If i RDP to the server, windows reports that it is using 28.4GB on the C drive

In the web client, the Usage is reporting 46.6GB Used for C drive

I would expect the C drive to be using at least 56.8GB (2 x 28.4GB)

The vsan.vm_object_info for the VM shows 2 x 23.3GB components for hard disk1 - which ties in with the usage figure being displayed in the web client

So my question is, if the OS is using 28.4GB, why is the component size smaller ?  As it is a hybrid array there is no compression or deduplication

Can anyone explain where this 'space saving' may be coming from ?

Thanks

[parmarr]

Hi, My first thought would be Windows reporting including swap files. Check the vSAN space reporting for swap objects too. I can also recommend getting a more details breakdown of the Windows filesystem using a tool like Windirstat and comparing it against vSAN object breakdown for that VM.