When is it possible to place a VMFS5 datastore in maintenance mode?

Storage DRS provides the datastore maintenance mode option, which automatically triggers Storage vMotion migrations to move virtual machine files off the datastore before it is taken offline for maintenance. A VMFS5 datastore must be a member of an SDRS cluster for the 'Enter Maintenance Mode' option to appear in vCenter - this is the only supported context for this feature with VMFS datastores.

Virtual SAN uses its own proprietary datastore type and management model; standard VMFS5 datastores cannot join a vSAN cluster and therefore cannot use vSAN-based maintenance workflows.

Multi-extent is an older VMFS construct that spans one datastore across multiple LUN extents for capacity purposes and does not provide or enable any maintenance mode functionality.

Virtual Volumes represent a different storage architecture where policies are applied per-VM object; VMFS5 datastores are not members of vVol constructs and cannot inherit maintenance mode from them.