vSAN Health Service - Cluster - Disk format version

Products

• VMware vSAN

Issue/Introduction

This article explains the Cluster - Disk format version check in the vSAN Health Service and provides details about why it might report an error.

Environment

VMware vSAN 7.x
VMware vSAN 8.x

Cause

Q: What does the Cluster Health - Disk format version test do?

• This test verifies the disk format version of all vSAN disks currently in use, and ensures that all vSAN disks use the highest disk format version that the host supports.

Q: What does it mean when it is in an error state?

• If this check returns a warning, it means that the disk format version of one or more vSAN disks are compatible, but out of date.
• To get full support of the latest vSAN features, on-disk upgrade is recommended.
• If this check returns an error, it means the disk format version of one or more vSAN disks have a disk format version that is out of date and is not compatible with other vSAN disks.
• vSAN cannot balance data across the disks, which can lead to problems creating or powering on VMs, performance degradation, EMM failures, and so on.
• This configuration must be fixed immediately.

Resolution

Q: How does one troubleshoot and fix the error state?

• If the result of this check is a warning, then it is reporting that a newer disk format version is available for upgrade.
• If the result is an error, it reports that the hosts are running on mixed versions of disk format.
• For both cases, a vSAN on-disk format upgrade is required to fix the issue.
• Click the On-disk Format Upgrade button on the vSphere Web Client: <vSAN Cluster> >Configure > vSAN > Disk Management

This is typically a non-disruptive process if going from version 5 and higher, but you could see a performance hit and is recommended to be run during non-peak business hours.

Note: After upgrading the disk groups to 3.0, only metadata upgrades are required. This does not require a full data evacuation

 

Note: It's best to run the Upgrade Pre-check prior to running the upgrade to ensure the upgrade will be successful.

Possible error seen when performing Upgrade pre-check:

1. "General vSAN error. Object(s) f82fe462-####-c1c7-####-3868dd66####, 11843d63-####-02da-####-3868dd66#### are inaccessible in vSAN.". It will not be possible to upgrade disk format version when there are inaccessible vSAN objects.
   1. First resolve the inaccessible vSAN objects issue.
   2. Then upgrade the on disk format version.

Refer to the following KB article for details regarding vSAN on-disk format versions and compatibility for each vSAN release:

Understanding vSAN on-disk format versions and compatibility