Data Domain: How to add disks to a tier when receiving message "Cannot add disks to tier unless the file system is expanded"

For DD6900, DD9400, and DD9900 systems, storage capacity licenses are available in increments of 60 TB raw (48 TB usable) capacity.

For systems with 8 TB drives, the licensed capacity might not equal the full capacity of the disks that are installed in the disk shelves.

If the system has one pack of 8 TB disks (96 TB usable capacity), but the licensed capacity is 48 TB, only half the system capacity is available for use.

If this happens, and you try to add more physical storage with shelf-specific capacity licenses for 3 TB or 4 TB disks, you see the error "Cannot add disks to tier unless the filesystem is expanded".
 

sysadmin@hostname# storage add tier active enclosure 2:2

Checking storage requirements...

**** Cannot add disks to tier unless the filesystem is expanded.

Observe the storage and license below.

The system's active tier is 218.3 TiB for five packs of 7.2 TiB disk.

It is the usable capacity between the 192 TB (174.48 TiB) for 4 packs of 8 TB disk and 288 TB (261.72 TiB) for five packs of 8 TB disk of an Over Provisioning (OP) enabled system.

Here, the active tier can be expanded to 261.72 TiB provided a correct size of CAPACITY-ACTIVE  HIGH_DENSITY license is installed in the system.

Until corrected, no additional storage can be added to the system. 

See the following article that discusses license capacity and usable storage function on an Over Provisioning (OP) enabled system.
Data Domain : 8 TB disk packs and Over Provisioning (OP) 
 

Storage Show All
----------------
Active tier details:
Disk      Disks                              Count   Disk       Additional
Group                                                Size       Information
-------   --------------------------------   -----   --------   -----------
dg2       2.1-2.3, 2.13-2.15, 2.25-2.27,     14      7.2 TiB
          2.37-2.39, 2.49-2.50
dg6       3.10-3.12, 3.22-3.24, 3.34-3.36,   14      7.2 TiB
          3.46-3.48, 3.58-3.59
dg5       3.7-3.9, 3.19-3.21, 3.31-3.33,     14      7.2 TiB
          3.43-3.45, 3.55-3.56
dg4       3.4-3.6, 3.16-3.18, 3.28-3.30,     14      7.2 TiB
          3.40-3.42, 3.52-3.53
dg3       3.1-3.3, 3.13-3.15, 3.25-3.27,     14      7.2 TiB
          3.37-3.39, 3.49-3.50
(spare)   2.51                               1       7.2 TiB
(spare)   3.51                               1       7.2 TiB
(spare)   3.54                               1       7.2 TiB
(spare)   3.57                               1       7.2 TiB
(spare)   3.60                               1       7.2 TiB
-------   --------------------------------   -----   --------   -----------

Current active tier size: 218.3 TiB
Active tier maximum capacity: 698.5 TiB


Cache tier details:
Disk    Disks       Count   Disk       Additional
Group                       Size       Information
-----   ---------   -----   --------   -----------
dg1     1.12-1.16   5       3.4 TiB
-----   ---------   -----   --------   -----------

Current cache tier size: 17.4 TiB


Storage addable disks:
Disk        Disks                            Count   Disk       Enclosure   Shelf Capacity   Additional
Type                                                 Size       Model       License Needed   Information
---------   ------------------------------   -----   --------   ---------   --------------   -----------
(unknown)   2.4-2.6, 2.16-2.18, 2.28-2.30,   15      3.6 TiB    DS60        43.6 TiB         pack 2
            2.40-2.42, 2.52-2.54
(unknown)   2.7-2.9, 2.19-2.21, 2.31-2.33,   15      3.6 TiB    DS60        43.6 TiB         pack 3
            2.43-2.45, 2.55-2.57
---------   ------------------------------   -----   --------   ---------   --------------   -----------

Shelf Capacity License:
License           Model          Total       Used        Remaining
---------------   ------------   ---------   ---------   ---------
CAPACITY-ACTIVE   HIGH_DENSITY   218.2 TiB   218.2 TiB   0.0 TiB   ===>>> License installed on an existing storage
CAPACITY-ACTIVE   DS60           87.3 TiB    0.0 TiB     87.3 TiB      ===>>>  License for 2 packs of 4TB disks that needs to be added 
---------------   ------------   ---------   ---------   ---------

To resolve: 
1. Update HIGH_DENSITY license to cover the existing storage capacity of the system.
2. Expand the FS.
3. Run "storage add" command to add new 3 TB or 4 TB packs.
4. Expand the FS again to put the new packs "in-use".