vSAN Health Service – Physical Disk Health

Products

VMware VMware vSAN

Issue/Introduction

This article explains the Physical Disk Health - Component Metadata Health check in the vSAN Health Service and provides details on why it might report an error.

Q: What does the Physical Disk Health – Component Metadata Health check do?
A: This health check verifies the integrity of the component metadata on a disk.

Symptoms:
vSAN cluster showing Component Metadata Health test failed in red state for one or more disks in one or more nodes.

Environment

VMware vSAN 6.2.x
VMware vSAN 7.0.x
VMware vSAN 6.1.x
VMware vSAN 6.7.x
VMware vSAN 6.6.x
VMware vSAN 6.0.x
VMware vSAN 8.0.x
VMware vSAN 6.5.x
VMware vSAN 6.6 Pre-release
VMware vSAN 5.5.x

Cause

Q: What does it mean when it is in an error state?
A: If this health status from this check is not green (OK), vSAN has encountered an issue with an individual component.

This error will not cause vSAN to decommission the disk on which the component resides. But in rare cases where bad metadata is detected, the problem might lead to additional issues with the object that contains the component. In particular, if the number of prepared I/O equals 255, or if the number of committed I/O is larger than 10,000, the Component metadata health check returns an error (this particular criteria was removed in vSphere 6.0 patch 03 and later releases).

Resolution

Q: How does one troubleshoot and fix the error state?
A: This error might be caused by faulty drives, a faulty controller, or a misbehaving device driver, but it might be intermittent and originate from the vSAN software. The best approach would be to isolate each storage component from the software and hardware layer, validating from the vendor's GUI if the information matches in the virtual layer in the Web client.

For more information about troubleshooting and monitoring vSAN objects and components, see the Troubleshooting vSAN Storage section of the VMware vSAN Diagnostics and Troubleshooting Reference Manual.
The commit I/O larger than 10,000 failure might be intermittent (this particular criteria was removed in vSphere 6.0 patch 03 and later releases). But other test failures might require VMware Support. For more information, see How to file a Support Request in Customer Connect (2006985).

Additional Information

For more information on collecting VMware vSAN logs, see Collecting vSAN support logs and uploading to VMware (2072796).

Additional resources: