Best Practice to Remove VMDK datastore access from ESXi hosts

Short Answer:

With the help of the storage plugin like AMS/VSM(EqualLogic), CITV(Compellent), VSI(PowerStore) or what ever the Unity version was named.

Long Answer:

It depends a little bit of the type if Datastore(iSCSI vs. FC) and for sure you have to start always on the Host level and than go backwards. In the good old times it was VMware KB 2004605.

There is deep water when this datastore was also used as a cache device, store core dumps or was the scratch partition.

Regards,

Joerg

@Origin3k​ it is FC and the SAN is DellEMC Unity 550f. We do not have a storage plugin on vSphere for Unity. We have always presented/attached vmdk datastores to esxi hosts from the Array UI.
So it sounds like it's best to just remove vmdk datastores from the Host level (Access-VMware-ESXi Hosts), one host at a time?

https://knowledge.broadcom.com/external/article/323128/how-to-detach-a-lun-device-from-esxi-hos.html

For a more summarized process I think correct steps would be in vSphere Unmount and Detach then in SAN remove host access from LUN
using the following Steps:

vSphere - Hosts and Clusters - Unmount and Detach

1. Select the ESXi host → Datastores → Right-click on the datastore and Unmount

2. Detach it via Configure → Storage Devices → click on the LUN I just unmounted and click "DETACH"

Then in Unisphere (SAN array UI) go to the LUN - Host Access tab and remove the ESXi host

That sound correct?

again I've only ever removed host access from the Unisphere SAN array UI which then rescans the esxi host in vSphere and removes access there.

You may have 

• Templates or ISO (configured vCDOM)
• Redirect your systemlogs
• Redirect scratch dir
• marked for storing vCLS
• configured as a HA Heartbeart

It all need to be undone befor you can umount a Datastore on a ESXi Hosts.

Regards,

Joerg