Capacity monitoring

As we do capacity monitoring at the datastore cluster level, it becomes important that we know how the numbers are derived. Let's use an example as a way to test our understanding.

The following example uses a datastore cluster that has three datastores. Each has 1 TB, mapped to a 1 TB LUN. Let's verify what contributes to the Free column.

Datastore information in vCenter

To verify whether it is based on Thin, I added all the VMs in the datastore cluster, shown in the next diagram:

VM storage information in vCenter

Notice that they did not add up to what we saw at the datastore level. At the datastore level, it shows that the usage is more than 130 GB. At the VM level, the total used space is less than 20 GB. Something does not tally. Can you guess four reasons that can contribute to this discrepancy?

Let's browse the datastore. We find the first reason: we have non-VM objects. In this case, we have ISO files.

Datastore – the file-browser UI

The following...