Datastore capacity and overcommit

The Datastores tab compares three different numbers that are easy to confuse: capacity, provisioned, and in use.

- **Capacity** is the size of the volume.
- **Provisioned** is the sum of what every VM on it was promised.
- **In use** is what has actually been written.

**Overcommit**

Provisioned divided by capacity. Above 1.0 the datastore has promised more space than it physically has -- normal with thin provisioning, and fine right up until the guests actually write what they were promised. The tile shows the estate-wide ratio and how many individual datastores are over capacity.

**Near full**

Any datastore whose free space is below your threshold, defaulting to 10 percent. The table is sorted least-free first, so the volume closest to trouble is the first row you see.

**Free space that was not reported**

Some exports omit the free-space column. When capacity and in-use are both present, free is derived from them rather than left blank.

**Datastores that could not be read**

A datastore with no readable capacity is reported with that reason and excluded from every estate total on the tab. It is not divided by -- a capacity of zero would turn the overcommit ratio into a number that looks real and means nothing.