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

2. From the table, select the THP V-VOL for which you want to change the name.
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).
3. Click Edit LDEVs.
When you selected THP V-VOLs from the Virtual Volumes table, click More Actions, and then
Edit LDEVs.
The Edit LDEVs window opens.
4. Check LDEV Name and change the LDEV name, if necessary.
1. In Prefix, type the characters that will become the fixed characters for the beginning of
the LDEV name. The characters are case-sensitive.
2. In Initial Number, type the initial number that will follow the prefix name.
5. Click Finish.
6. In the Confirm window, confirm the settings, 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.
About releasing pages in a THP V-VOL
Releasing pages in a THP V-VOL frees up pool capacity. When all the pages in the THP V-VOL
contain zero data (no logical records), you can discard the zero data, and then release those
pages.
Logically, there is no difference between a page with just zero data and the area of a THP V-VOL
without a page allotted. They are effectively identical. However, the former uses pool capacity
and the latter does not.
Zero data can be discarded when all the following conditions are satisfied:
• The THP V-VOL is not used in conjunction with another P9500 product that does not support
discard zero data.
See “Using Thin Provisioning Z with other P9500 products” (page 50).
• LDEV formatting is not being performed on the THP V-VOL.
• The THP V-VOL is not blocked.
• The THP V-VOL is associated with a pool.
• The pool associated with the THP V-VOL is not blocked, or is full and blocked.
Pages that include control cylinders are not processed when releasing pages in a THP V-VOL.
While releasing pages from a THP V-VOL, performance of the host I/O to the THP V-VOL may
temporarily decrease due to scanning for non-zero data.
If you stop discarding zero data in mid-stream, the pages that have been released will remain as
free pool capacity.
After the zero data is discarded and the pages are released, Thin Provisioning Z automatically
balances usage levels among pool-VOLs in the pool. This rebalancing is performed on all of the
THP V-VOLs and pool-VOLs in the pool. If you do not want automatic balancing of the usage levels
of pool-VOLs, call the HP Technical Support to change your configuration.
Thin Provisioning Z does not automatically balance the usage levels among pool-VOLs if the cache
memory is not redundant or if the pool usage level exceeds the thresholds.
If all the data written to a page assigned to a THP V-VOL is binary zeroes, you can reclaim the
page and return it to the pool's available capacity.
Managing pools and THP V-VOLs 67