Removing a disk unit from an auxiliary storage pool

You need to remove a disk unit from an auxiliary storage pool (ASP) for these reasons.

You want to physically remove a disk unit from your system.
You want to move a disk unit from an ASP that has mirrored protection to another ASP. You can remove pairs of disk units from a mirrored ASP without stopping mirrored protection. You then add the disk units to the target ASP.

Considerations when changing your ASP configuration: Consider these things when you are planning to remove disk units from an ASP:

The system might take a long time to remove the unit because it must copy the data from that unit to other units in the ASP.
To proceed, the system must perform internal processing that might take several minutes during which the system might appear inactive.
When you remove a disk unit, it becomes nonconfigured.

Restrictions when changing your ASP configuration: Consider these restrictions when you are planning to remove disk units from an ASP:

You cannot remove unit 1 (the load source unit) from the system ASP.
You cannot remove disk units from a user ASP that is overflowed.
When mirrored protection is active for the ASP that contains the disk units, you must remove both units of a mirrored pair.
If you are going to physically remove a disk unit from an input/output adapter (IOA), you must either exclude the disk unit or stop device parity protection first.

This task describes how to remove a disk unit with dedicated service tools (DST). For other ways to remove a disk unit, see Removing a disk unit from a disk pool.

To remove a disk unit, follow these steps:

If you are not already using dedicated service tools (DST), perform a manual initial program load (IPL) to start DST.
From the Use Dedicated Service Tools (DST) menu, follow these steps:
1. Select option 4 (Work with disk units).
2. Select option 1 (Work with disk configuration) on the Work with Disk Units display.
3. Select option 3 (Work with ASP configuration) on the Work with Disk Configuration display.
4. Select option 7 (Work with removing units from configuration) on the Work with ASP Configuration display.
5. Select option 3 (Remove units from configuration) on the Work with Removing Units From Configuration display.

You are shown the Remove Units from Configuration display.

                       Remove Units from Configuration
 
Type options, press Enter.
  4=Remove unit from configuration
 
                 Serial                     Resource
OPT  Unit  ASP   Number      Type   Model   Name            Status
      2     1    10-00A7529  9332   400     DD010           Configured
      3     1    10-00A4936  9332   400     DD012           Configured
      4     1    10-00A4936  9332   400     DD019           Configured
 4    5     1    10-00A7498  9332   400     DD025           Configured
 4    6     1    10-00A7498  9332   400     DD036           Configured
      7     1    10-00A7530  9332   400     DD042           Configured
      8     1    10-00A7530  9332   400     DD052           Configured

Type a 4 (Remove unit from configuration) in the OPT column for each unit that you want to remove and press the Enter key.
If the remove operation would leave the ASP with insufficient storage, you receive an error message.
If you see the Confirm Remove Disk Units display, skip to 6.

The Confirm Continuation display might be shown before the Confirm Remove Disk Units display if the storage management directories are not usable.
```
                              Confirm Continuation
 
To proceed, the system must perform internal processing
that might take several minutes during which the system might
appear inactive.
 
Press Enter to continue.
Press F12=Cancel to return and change your choice.
```
Determine whether you want to cancel the procedure or continue.
If you want to continue, press the Enter key.

The Confirm Remove Disk Units display is shown:

                             Confirm Remove Disk Units
 
Removing disk units will take several minutes.
 
Press Enter to confirm remove of disk units.
Press F9=Capacity information to display the capacity information.
Press F12=Cancel to return to change your choice.
 
 
                 Serial                     Resource
OPT   Unit  ASP  Number      Type   Model   Name            Status
 4      5    1   10-00A7498  9332    400    DD010           Configured
 4      6    1   10-00A7498  9332    400    DD012           Configured

Press F9 (Capacity information to display the resulting capacity.

                               Resulting Capacity
 
The configuration change that you requested would result in the
following ASP capacities.
 
Press Enter to continue.
               -----------Current----------  ----------Modified--------
               --Protected--  -Unprotected-  --Protected-- -Unprotected-
ASP   Threshold  Size  %Used   Size  %Used   Size   %Used   Size   %Used
 1        90%       0   0.00%  1600  52.70%     0    0.00%  1200   70.26%

Press the Enter key to return to the Confirm Remove Disk Units display.
Press the Enter key on the Confirm Remove Disk Units display to remove the selected units.
The system moves the data off the units selected to be removed to the remaining units in the source ASP. The remove can take several minutes or several hours during which the system appears inactive.
Notes:
- The time it takes to remove a unit depends on the disk unit type and model.
- If the data on the unit being removed is severely fragmented and the amount of storage used is high, the remove operation might take several hours.

When the remove operation is complete, you return to the Work with ASP Configuration display. If you have no other tasks to perform, end DST.