I need some help creating a supermetric to show a ratio between the percentage of space overprovisioned on a datastore to the percentage of free space on a datastore.
In plain math, let's say we have a 1TB datastore. That datastore has 1.5TB provisioned (using the vCenter terminology). That same datastore has 400GB of free space remaining. So the datastore 150% provisioned (1.5/1). There is also roughly 40% free space remaining (400/1024). I want to create a supermetric that shows that the 150% / 40% = 3.75. Since we use thin provisioning exclusively (we have all NFS), the amount of overprovsioning relative to the amount of free space remaining is very important.
The equation is simple enough, but I've been having a difficult time finding the proper metrics. The size of the datastore and the free space on the datastore I had no problem with. However, finding what has been provisioned is a different matter. 1) I can't find one that matches what is reported in vCenter, and 2) they tend to be slightly different, and I don't understand the differences.
On the datastore in question there is 2.85TB provisioned (2918.4GB). However...
Capacity|Provisoned Consumer Space (GB) = 2,442GB
Disk Space|Provisioned Space (GB) = 2,665GB
Neither is 2918, but what is the 200GB difference? Even if I add Snapshot Space and Swapfile Space, which are only 28GB combined, I come up well short.
Any thoughts, ideas, suggestions?