vSAN Object Format Change task fills vSAN datastore and resync is suspended

Products

• VMware vSAN

Issue/Introduction

Symptoms:

• vSAN datastore utilization increases after initiating vSAN object format change task.

• The vSAN "Operations Usage" space utilization is very large:

  

• Resync does not progress as there is not enough space on a few vSAN disks:

  
  "Resynchronization has been suspended for some objects because there is not enough storage space on one or more disk groups. Check cluster health for details."

• Cancelling the vSAN object format change task does not release the space consumed by "Operations usage".

Environment

VMware vSAN 7.x

Cause

During the object format change process, vSAN create a complete copy of the original object in the new format, so this will make the object consume 2x the space. Once the format change completes for the object, the old format part is deleted.

If large objects exist in the cluster then this process can possibly end up filling the vSAN datastore.

Resolution

We will need to either free up space or add more storage to let the vSAN object format change task to complete.

To free up space on vSAN datastore we have the below options:

• Delete snapshot from VMs.

• Clear up any unwanted inaccessible and unassociated vSAN objects. (Dealing with inaccessible objects in a vSAN cluster. & Procedures for identifying Unassociated vSAN objects)

• Migrate VM off to another datastore temporarily, if available.

• Change storage policy of VM to no-redundancy (FTT=0). Be aware that if this policy is used the VM's objects will not have storage redundancy.

If you cannot implement any of the above options, please contact Broadcom Support to explore other possible options.

Additional Information

Initiating vSAN Object Format Change - Skyline Health - vSAN object format health