vSAN space reporting feature overview

VMware vSAN

This article describes the vSAN space reporting feature and the space usage data definitions shown in space reporting.

VMware vSAN 7.0.x
VMware vSAN 6.2.x
VMware vSAN 6.7.x
VMware vSAN 6.5.x
VMware vSAN 6.1.x
VMware vSAN 8.0.x

Q: What does the space reporting feature do?
A: vSAN space reporting is enabled by default in vSAN 6.2 and later releases.

Using the vSAN space, you can view this information:

General vSAN space usage.
Detailed space usage breakdown that indicates the total amount of used and free space that is available.
The purpose for which the space is used.

Q: What is the meaning of each reported data value shown in the space reporting view?
A: The space reporting page includes three portals:

The space usage data definition in the capacity overview portal are listed here.

Provisioning: Logical capacity configured for all objects on the cluster
Used - Physically Written: Capacity storing actual data of the objects on the vSAN datastore
Used - VM Over-reserved: Space wasted due to higher than needed space reservation setting. Reducing the object space reservation policy can free up space without the need to delete or move any data
Used - Total: Space not available for new allocations
Used - vSAN system overhead: Capacity consumed by vSAN for system needs.

There are two types of capacity breakdown, object types and data types.

Object type breakdown

Virtual disks: The total space used for all of the virtual disks
VM home objects: The total space used for the VM home directory
Performance management object: The total space used for the vSAN performance service
Vmem: The total space used for the virtual memory for all VMs
File system overhead: The vSAN file system overhead
Checksum overhead: The space required for checksum metadata overhead
The deduplication and compression overhead: The metadata overhead required for deduplication and compression
The snapshot memory: The total space used for the snapshot memory
Other: Any other used space such as the user-created file or the VM template in the vSAN datastore

Data type breakdown

Primary VM data: The total space used for primary VM data. This is user used data in VM/VMDK
vSAN overhead: The total of all kinds of vSAN overhead including replica, witness, RAID 5/6 component, and so on
The temporary overhead: The space used when moving objects

Used space before: The total used space before enabling deduplication and compression
Used space after: The total used space after enabling deduplication and compression
Saving: The total space savings achieved by enabling deduplication and compression