Loss of communication will produce a "Permanent Device Loss" condition in the VMware host.
The reason why a 'self heal' will not occur is because of how VMware handles a complete path loss event without error codes.
This will happen when there is a network issue that interrupts communication from the VMware host to the iSCSI Targets on the QuantaStor box. This loss of communication will produce a "Permanent Device Loss" condition in the VMware host due to the lack of any SCSI sense codes being returned from the Targets (since it is a complete communication loss, as compared to other issues that could produce SCSI sense codes).
To clean up an unplanned PDL:
1. All running virtual machines from the datastore must be powered off and unregistered from the vCenter Server.
2. From the vSphere Client, go to the Configuration tab of the ESXi host, and click Storage.
3. Right-click the datastore being removed, and click Unmount.
The Confirm Datastore Unmount window displays. When the prerequisite criteria have been passed, the OK button appears.
If you see this error when unmounting the LUN:
Call datastore refresh for object <name_of_LUN> on vCenter server <name_of_vCenter> failed
You may have a snapshot LUN presented. To resolve this issue, remove that snapshot LUN on the array side.
4. Perform a rescan on all of the ESXi hosts that had visibility to the LUN.
Note: If there are active references to the device or pending I/O, the ESXi host still lists the device after the rescan. Check for virtual machines, templates, ISO images, floppy images, and raw device mappings which may still have an active reference to the device or datastore.
5. If the LUN is still being used and available again, go to each host, right-click the LUN, and click Mount.
Additional details can be found on the VMware web site: