Search the VMware Knowledge Base (KB)
View by Article ID

vSAN space reporting feature overview (2144399)

  • 0 Ratings


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


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 these 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.
vSAN space reporting is enabled by default in vSAN 6.2 and later releases. It displays general vSAN space usage,  displays a detailed space usage breakdown that indicates the total amount of used and free space that is available, and 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:
  • capacity overview portal
  • capacity breakdown portal
  • deduplication and compression overview ports
The space usage data definition in the capacity overview portal are listed here.

Capacity Overview

  • 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 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.

Used Capacity Breakdown

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

Object type breakdown

  • Virtual disks: The total space used for all of virtual disks
  • VM home objects: The total space used for the VM home directory
  • Performance management object: The total space used for 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

Deduplication and compression overview

  • 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

See Also

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


  • 0 Ratings

Did this article help you?
This article resolved my issue.
This article did not resolve my issue.
This article helped but additional information was required to resolve my issue.

What can we do to improve this information? (4000 or fewer characters)

Please enter the Captcha code before clicking Submit.
  • 0 Ratings