This topic explains how to calculate the capacity of a VSA cluster with 4, 6, or 8 hard disks per ESXi host and a RAID10 configuration.
The capacity of the VSA cluster that uses this configuration depends on two variables.
■
 
■

The capacity of a VSA datastore equals the total hard disk capacity of the ESXi host divided by 4. This is due to the RAID10 configuration on each ESXi host and the mirroring of VSA volumes between VSA cluster members.
Determine the VSA datastore capacity by using the following formula.
VSA datastore capacity = hard disk capacity of an ESXi host / 4
hard disk capacity of an ESXi host = the total capacity of the hard disks that are installed internally on the ESXi host
If you create a VSA cluster with hosts that have different total hard disk capacities, the lowest hard disk capacity from all ESXi hosts becomes the basis for calculating the capacity of every VSA datastore. In such a situation, some of the total hard disk capacity remains unused.
Hard disk capacity per ESXi host = 8TB
Total hard disk capacity of all ESXi hosts = 24TB
VSA datastore capacity = 8TB / 4 = 2TB
Total VSA cluster capacity = 2TB * 3 hosts = 6TB
Hard disk capacity of ESXi host 1 = 6TB
Hard disk capacity of ESXi host 2 = 8TB
Hard disk capacity of ESXi host 3 = 8TB
Total hard disk capacity = 22TB
VSA datastore capacity = 6TB / 4 = 1.5TB
Total VSA cluster capacity = 1.5TB * 3 hosts = 4.5TB