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

RequirementsItems
You can reduce pool capacity by removing pool-VOLs.Reducing capacity
You can delete pools that are not associated with any THP V-VOLs.Deleting
You can set the subscription limit on a THP V-VOL. This limits the percentage of THP V-VOL
capacity that can be created for the pool capacity and avoids THP V-VOL blocking caused by
a full pool.
Subscription limit
When the subscription limit is, for example, set to 100%, the formula for calculating the THP
V-VOL capacity that can be created is as follows. The total THP V-VOL capacity must include
the capacity of the control cylinders (required 7 cyl per 1,113 cyl) of each THP V-VOL (3390-A
type).
total THP V-VOL capacity <= pool capacity × 100%
This setting can restore the ability to shrink the pool, create the THP V-VOL, and expand the THP
V-VOL.
Utilization thresholds
• Warning Threshold: You can set the value between 1% and 100%, in 1% increments. The
default is 70% (recommended).
• Depletion Threshold: You can set the value between 1% and 100%, in 1% increments. The
default is 80%.
Pool usage over either threshold will cause a warning to be issued via a SIM reported to Remote
Web Console and an SNMP trap reported to the open-systems host
38 MBData allocation unit
(page)
The 38-MB page corresponds to a 38-MB continuous area of the THP V-VOL. Pages are allocated
only when data has been written to the area of the THP V-VOL.
Pool-VOL requirements
Pool-VOLs make up a THP-pool.
RequirementsItems
Logical volume (LDEV)Volume type
For best performance, pool-VOLs for a pool should not share a parity group with other volumes.
Pool-VOLs cannot be used for any other purpose. For instance, you cannot specify the following
volumes as Thin Provisioning Z pool-VOLs:
• Volumes used by Business Copy Z, Continuous Access Synchronous Z, or Continuous Access
Journal Z
• Volumes defined by Cache Residency Manager
• Volumes already registered in Thin Provisioning Z pools
• Volumes whose LDEV status is other than Normal or Normal (Quick Format)
You cannot specify volumes in blocked status or volumes in copying process.
• System disks
• Command devices
The following pool-VOLs cannot exist in the same pool:
• Internal volumes and external volumes whose cache mode is disabled.
• External volumes whose cache mode is enabled and external volumes whose cache mode
is disabled.
3390-VEmulation type
Any RAID levels other than RAID 1 can be used for pool-VOLs. RAID 5, RAID 6, and the external
volume can coexist in the same pool.
RAID level for a Thin
Provisioning Z pool
Thin provisioning requirements 47