DellEMC Data Domain - Disk state

Disk State	Description	Action
In Use	The number of disks currently in use by the file system.	No Action required
Spare	The number of spare disks (available to replace failed disks).	No Action required
Spare (reconstructing)	The number of disks that are in the process of data reconstruction (spare disks replacing failed disks).	No Action required
Available	The number of disks that are available for allocation to an Active or DD Extended Retention storage tier.
Known	The number of known unallocated disks.	Resolve Disk State "Known"
Unknown	The number of unknown unallocated disks.	Resolve Disk State "Unknown"
Failed	The number of failed disks.
Foreign	The number of foreign disks.
Absent	The number of absent disks.
Migrating	The number of disks serving as the source of a storage migration.
Destination	The number of disks serving as the destination of a storage migration.
Not Installed	The number of empty disk slots that the system can detect.