When you unmount a datastore in the VMware Host Client, it remains intact, but you can no longer view it in the inventory of the host that you manage. The datastore continues to appear on other hosts that it remains mounted on.

Do not perform any configuration operations that might result in I/O to the datastore while the unmounting is in progress.

Prerequisites

Note: Make sure that the datastore is not used by vSphere HA heartbeating. vSphere HA heartbeating does not prevent you from unmounting the datastore. However, if the datastore is used for heartbeating, unmounting it might cause the host to fail and restart all active virtual machines.
Before unmounting a datastore, also make sure that the following prerequisites are met:
  • No virtual machines reside on the datastore.
  • Storage DRS does not manage the datastore.
  • Storage I/O Control is deactivated for this datastore.

Procedure

  1. Click Storage in the VMware Host Client inventory and click Datastores.
  2. Right-click the datastore to unmount from the list and click Unmount.
  3. Confirm that you want to unmount the datastore.

Unmounting or Removing Datastore Fails

When you try to unmount or remove a datastore, the operation fails.

Problem

The operation to unmount or remove a datastore fails if the datastore has any opened files. For these user operations, the vSphere HA agent closes all the files that it has opened, for example, heartbeat files. If the agent is not reachable by vCenter Server or the agent cannot flush out pending I/Os to close the files, a The HA agent on host '{hostName}' failed to quiesce file activity on datastore '{dsName} fault is triggered.

Cause

If the datastore to be unmounted or removed is used for heartbeating, vCenter Server excludes it from heartbeating and chooses a new one. However, the agent does not receive the updated heartbeat datastores if it is not reachable, that is, if the host is isolated or in a network partition. In such cases, heartbeat files are not closed and the user operation fails. The operation can also fail if the datastore is not accessible because of storage failures such as all paths down.

Note: When you remove a VMFS datastore, the datastore is removed from all the hosts in inventory. So if there are any hosts in a vSphere HA cluster that are unreachable or that cannot access the datastore, the operation fails.

Solution

Ensure that the datastore is accessible and the affected hosts are reachable.