Adding NetBackup 5220 expansion unit fails with "Failed to add the expansion unit device storage"

Problem

When trying to add an expansion unit to a 5220 appliance, it fails.

Error Message

Command to add the unit fails as follows:

5220hostname.Storage> Add unit_2
- [Info] Checking the type of the 'unit_2' device...
- [Info] Checking the state of the 'unit_2' expansion unit device storage...
- [Info] Initializing 'unit_2' expansion storage...
- [Info] Configuring 'unit_2' expansion unit storage...
- [Info] Adding 'unit_2' expansion unit storage space to 'Unallocated' space...
- [Error] Failed to add the expansion unit device storage.

In /log/.LOGROOT/APPLIANCE/app_change_control.log we see:

[11-27-2012 11:27:57] [30115] cmd:" /opt/VRTS/bin/vxdiskunsetup disk_2"( 0 )
[11-27-2012 11:27:58] [30115] cmd:" /usr/sbin/parted /dev/sdc mklabel gpt"( 0 )
[11-27-2012 11:27:59] [30115] cmd:" /opt/VRTS/bin/vxdisksetup -i disk_2 format=sliced"( 0 )
[11-27-2012 11:27:59] [30115] cmd:" /opt/VRTS/bin/vxdg -g nbuapp adddisk disk_2"( 12 )
stderr: VxVM vxdg ERROR V-5-1-559 Disk disk_2: Name is already used

Cause

The failure is due to device name conflict in Veritas Volume Manager (vxvm). Device "disk_3" has a vxvm disk name of "disk_2"

Example:
# vxprint -htg nbuapp

dm disk_1       disk_1       auto     65535    9755774656 -
dm disk_2       disk_3       auto     65535    76171777984 -

# vxdisk list
DEVICE       TYPE            DISK         GROUP        STATUS
disk_1       auto:sliced     disk_1       nbuapp       online
disk_2       auto:sliced     -            -            online
disk_3       auto:sliced     disk_2       nbuapp       online
sda          auto:none       -            -            online invalid

Solution

Rename the disk name to match the DEVICE name.

# vxedit -g nbuapp rename disk_2 disk_3

Vxvm should now show the following:

# vxdisk list
DEVICE       TYPE            DISK         GROUP        STATUS
disk_1       auto:sliced     disk_1       nbuapp       online
disk_2       auto:sliced     -            -            online
disk_3       auto:sliced     disk_3       nbuapp       online
sda          auto:none       -            -            online invalid

Proceed to add expansion unit

5220hostname.Storage> Add unit_2
- [Info] Checking the type of the 'unit_2' device...
- [Info] Checking the state of the 'unit_2' expansion unit device storage...
- [Info] Initializing 'unit_2' expansion storage...
- [Info] Configuring 'unit_2' expansion unit storage...
- [Info] Adding 'unit_2' expansion unit storage space to 'Unallocated' space...
- [Info] Succeeded.

Applies To

NetBackup 5220 Appliance with two Expansion Shelves.