vSAN space reporting feature overview

Products

• VMware vSAN

Issue/Introduction

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

Environment

VMware vSAN 7.0.x
VMware vSAN 8.0.x

Resolution

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:

• 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 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.

Used Capacity Breakdown

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

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

Additional Information

Monitor vSAN Capacity