HP P9000 Provisioning for Mainframe Systems User Guide (AV400-96369, October 2011)

If you have started a discard zero data operation, and the storage system losses power, which
then disrupts shared memory, the discard zero data operation will not automatically continue after
the storage system restarts.
In any of the following cases, discarding of zero data will stop, and THP V-VOL pages will not be
released.
• LDEV formatting was performed while discarding zero data.
• The pool-VOL that is being accessed by the target THP V-VOL was blocked.
• The pool associated with the target THP V-VOL was blocked while discarding zero data.
• Cache memory failure occurred while discarding zero data.
• The THP V-VOL was released when zero data was discarded.
• The initial copy operation between Continuous Access Synchronous Z pair or Continuous
Access Journal Z pair was performed on the THP V-VOL in which the zero data was discarded.
Releasing pages in a THP V-VOL
You can release pages in a THP V-VOL to free pool capacity. If all the pages in the THP V-VOL
contains zero data (no logical records), you can discard the zero data, and then release those
pages. Before releasing pages in a THP V-VOL, see “About releasing pages in a THP V-VOL” (page
67)).
Procedure 10 To release pages in a THP V-VOL
1. In the Remote Web Console main window, in the Storage Systems tree, select a pool associated
with the THP V-VOLs whose pages are released. The pool information appears on the right.
Pool.
2. Click the Virtual Volumes tab.
3. From the Virtual Volumes table, select the THP V-VOL for which you want to release the pages.
Select multiple THP V-VOLs using the Shift key (if the THP V-VOLs are adjacent), or using the
Ctrl key (if the THP V-VOLs are not adjacent).
4. Click More Actions, and then select Reclaim Zero Pages.
The Reclaim Zero Pages window opens.
You cannot release pages in a THP V-VOL when the THP V-VOL is not in a normal status or
the THP V-VOL is discarding zero data.
5. In Task Name type a unique name for this task or accept the default, and then click Apply.
If Go to tasks window for status is checked, the Tasks window opens.
After discarding zero data and releasing pages in the THP V-VOL is complete, click Refresh in
Remote Web Console to update the Page Status. If the Page Status is not immediately updated,
wait a while, and then click Refresh again.
Stopping the release of pages in a THP V-VOL
1. In the Remote Web Console main window, in the Storage Systems tree, select a pool associated
with the THP V-VOLs in which the pages are being released. The pool information appears
on the right.
2. Click the Virtual Volumes tab.
3. From the Virtual Volumes table, select the THP V-VOL for which you want to stop releasing
pages.
Select multiple THP V-VOLs using the Shift key (if the THP V-VOLs are adjacent), or using the
Ctrl key (if the THP V-VOLs are not adjacent).
4. Click More Actions, and then select Stop Reclaiming Zero Pages.
The Stop Reclaiming Zero Pages window opens.
68 Configuring thin provisioning