Over the past couple of weeks i’ve been helping our Ops Team decommission an old storage array. Part of the process is to remove the datastore mounts and paths to ensure a clean ESXi Host config as well as remove any vCenter Tags that are used for vCloud Director Storage Policies.

Looking through my post archive I came across this entry from 2013 that (while relating to ESXi 4.1) shows you that there can be bad consequences if you pull a LUN from a host in the incorrect manner. Also if you are referencing datastores through storage policies and vCenter Tags in vCloud Director an incorrectly removed datastore will throw errors for the Virtual DC and Provider vDC from where the datastores used to be referenced.

With that, below is the process I refined with the help of an excellent set of PowerCLI commandlets provided by the Module created by Alan Renouf.

Step 1 – Remove Any vCenter Tags:

After this has been done you can go into vCloud Director and Refresh the Storage Policies which will remove the datastores from the Providers.

Step 2 – Import Datastore Function Module:

Step 3 – Connect to vCenter, Dismount and Detach Datastore

What the above commands do is check to see what Hosts are connected to the datastore being removed and what paths exist. You then run the Unmount command to unmount from the host and the Detach command removes all the paths from the host.

Step 4 – Refresh Storage on Hosts

The last step is to refresh the storage to remove all reference of the datastore from the host.

I did encounter a problem on a couple of hosts during the unmount process that returned the error as shown below:

This error is actually caused by a VSAN module that actively stores traces needed to debug any VSAN related issues on VMFS datastores…not really cool when VSAN isn’t being used, but the fix is a simple one as specified in this KB.