VMWare Cluster - Remove datastore failed - The vSphere HA agent on host '10.0.0.1' failed to quiesce file activity on datastore '/vmfs/volumes/XXXXXXXXXXXXX'. To proceed with the operation to unmount or remove a datastore, ensure that the datastore is accessible, the host is reachable and its vSphere HA agent is running.

For the last few days I do some reorganization of our Virtual Infrastructure. One of the steps of this reorganization is upgrade from VMFS 3 to VMFS 5 for all our storages connected to the main HA cluster.

Although it is possible in ESXi to upgrade to VMFS5 in-place, I decided to completely remove and re-create storages. The main reason was that previously all arrays were sliced in several 2TiB(-1MiB) logical drives, and I wanted to create single logical unit for each storage subsystem.

But almost each time I tried to remove an old datastore from ESXi, I've received an error:


Status: The vSphere HA agent on host '10.0.0.1' failed to quiesce file activity on datastore '/vmfs/volumes/XXXXXXXXXXXXX'. To proceed with the operation to unmount or remove a datastore, ensure that the datastore is accessible, the host is reachable and its vSphere HA agent is running.


Tip:
Well, solution is quite simple. Just go to the host which generated this error (in my example it's 10.0.0.1) in "Inventory > Hosts and Clusters" view, and remove a the datastore from the Summary tab of that host.