IBM DS8000 manual Figure B-36 Ending allocation for existing disk units

down time associated with removing a disk unit. This will keep new allocations away from the marked units.

Start ASP Balance (STRASPBAL)

Type choices, press Enter.

Balance type . . . .		. . . . . .	> *ENDALC	*CAPACITY, *USAGE, *HSM...
Storage unit . . . .		. . . . . .		1-4094
	+ for more values
				Bottom
F3=Exit	F4=Prompt	F5=Refresh	F12=Cancel	F13=How to use this display
F24=More keys
Figure B-36 Ending allocation for existing disk units

When you subsequently run the OS/400 command STRASPBAL TYPE(*MOVDTA) all data will be moved from the marked units to other units in the same ASP, as shown in Figure B-37.Clearly you must have sufficient new capacity to allow the data to be migrated.

	Start ASP	Balance (STRASPBAL)
Type choices, press Enter.
Balance type . . . .	. . . . . . >	*MOVDTA	*CAPACITY, *USAGE, *HSM...
Time limit	. . . . . .		1-9999 minutes, *NOMAX
			Bottom
F3=Exit F4=Prompt	F5=Refresh	F12=Cancel	F13=How to use this display
F24=More keys
Figure B-37 Moving data from units marked *ENDALC

You can specify a time limit that the function is to run for each ASP being balanced or the balance can be set to run to completion. If the balance function needs to be ended prior to this, use the End ASP Balance (ENDASPBAL) command. A message will be sent to the system history (QHST) log when the balancing function is started for each ASP. A message will also be sent to the QHST log when the balancing function completes or is ended.

If the balance function is run for a few hours and then stopped, it will continue from where it left off when the balance function restarts. This allows the balancing to be run during off hours over several days.

In order to finally remove the old units from the configuration, you will need to use Dedicated Service Tools (DST) and re-IPL the system (or partition).

Using this method allows you to remove the existing storage units over a period of time. However, it does require that both the old and new units are attached to the system at the same time so it may require additional IOPs and IOAs if migrating from an ESS to a DS8000.

It may be possible in your environment to re-allocate logical volumes to other IOAs, but careful planning and implementation will be required.

402DS8000 Series: Concepts and Architecture