The capacity consumption on VM summary page for the VM does not correspond to the size allocated by the user for the same VM in the vSAN cluster.

Products

• VMware vSAN

Issue/Introduction

Symptoms:

The user creates a VM with a 100 GB vmdk, and on the VM summary page, the user notices that the capacity utilization is 200GB.

Resolution

This is not an issue. The calculation is based on the policy selected for the VM. For example, a 100GB virtual disk that is mirrored (RAID-1/FTT=1) to withstand the loss of one drive or host requires up to 200GB of raw capacity—100GB for each mirror. If that 100GB virtual disk must withstand two simultaneous failures (FTT=2), three mirrored copies are needed, which requires up to 300GB of raw capacity.

For more information, please check the following blog post.

Capacity consumption using vSAN Policies