vSAN Health Service - Physical disk - Component limit

Products

• VMware vSAN

Issue/Introduction

This article explains the Physical disk - Component limit 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

Resolution

Q: What does the Physical disk - Component limit test do?

This test verifies that the number of vSAN components on the disk has not exceeded the components per disk limit.

Note: As of vSAN 8.0 it verifies both the data component and metadata component limit on the disk when vSAN ESA is enabled.

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

If the test returns a warning or error, it means that the number of vSAN components on the disk has reached its limit. Once the components per disk limit has been reached, the deployment of new virtual machines fails, and rebuild operations cannot be completed.

 

Each ESA disk is limited to 3000 DATA components and 3000 metadata components. This means if the host only has Two ESA disks, you will be limited to 6000 DATA components and 6000 metadata components which is well below the 27000 component limit of a single ESA host.  

 

If all disks have reached the component limit this will prevent the deployment of new VMs in the ESA cluster.  

These are the thresholds at which warnings and errors are displayed for this health check:

• Green (OK) - 75%
• Yellow (Warning) 75-95%
• Red (Danger) - Higher 95%

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

To troubleshoot this issue, add additional disks or remove any unneeded data form the cluster for any host that is reporting the error. For more information about the host component limit, refer to KB 315533.

Additional Information