HP XP7 Storage - Manual (Page 13)

38-MB pool pages are assigned on demand to any of the THP V-VOLs that are connected to that
pool. Other pages assigned over time to that THP V-VOL randomly originate from the next free
page of some other pool volume in the pool.
THP V-VOLs are defined as 3390-A volumes that can be larger than traditional volumes. This
volume type was created to reduce device address requirements.
Setting up a Thin Provisioning Z environment requires a few extra steps. You still configure various
array groups to a desired RAID level and create one or more 3390-V volumes (LDEVs) on each of
them (see
“Creating an LDEV” (page 40) ). Then set up a Thin Provisioning Z environment by creating
one or more THP pools of physical storage space that are each a collection of some of these
3390-V LDEVs (THP pool volumes). This pool structure supports creation of 3390-A Thin Provisioning
Z virtual volumes (THP V-VOLs), where 38-MB pages of data are randomly assigned on demand.
For detailed information, see “Configuring thin provisioning ” (page 54) .
When to use Thin Provisioning Z
Thin Provisioning Z is a best fit in a mainframe environment in the following scenarios:
•
Where the aggregation of storage pool capacity usage across many volumes provides the
best opportunity for performance optimization.
•
For stable environments and large consistently growing files or volumes.
•
Where device addressing constraints are a concern.
Thin Provisioning Z advantages
With Thin Provisioning Z Without Thin Provisioning Z Advantages
You can logically allocate more capacity than
is physically installed. You can purchase less You must purchase physical disk capacity for
expected future use. The unused capacity adds Reduces initial costs
capacity, reducing initial costs and you can add
capacity later by expanding the pool. costs for both the storage system and software
products.
When physical capacity becomes insufficient,
you can add pool capacity without service
interruption. You must stop the disk array to reconfigure it. Reduces
management costs
You can allocate volumes of up to 262,668 cyl
(223,257 GB) regardless of the physical disk
capacity. This improves management flexibility. As the expected physical disk capacity is
purchased, the unused capacity of the storage
system also needs to be managed on the Reduces
management labor
and increases
HP XP7 Storage product licenses are based on
used capacity rather than the total defined
capacity.
storage system and on licensed HP XP7
Storage products. availability of
storage volumes for
replication
Effectively combines I/O patterns of many
applications and evenly spreads the I/O activity Because physical disk capacity is initially
purchased and installed to meet expected Increases the
performance
across available physical resources, preventing future needs, portions of the capacity may be efficiency of the data
drive
bottlenecks in parity group performance. unused. I/O loads may concentrate on just a
Configuring the volumes from multiple parity subset of the storage which might decrease
performance.
groups improves parity group performance. This
also increases storage use while reducing power
and pooling requirements (total cost of
ownership).
Thin Provisioning Z advantage example
To illustrate the merits of a Thin Provisioning Z environment, assume you have twelve 3390-V LDEVs
from 12 RAID 1 (2D+2D) array groups assigned to a THP pool. All 48 disks contribute their IOPS
and throughput power to all 3390-A THP volumes assigned to that pool. If more random read
IOPS capability is desired for a pool, it can be defined with 32 3390-V LDEVs defined using RAID
5 (3D+1P) array groups. This provides 128 disks to the pool and workload is spread across all
When to use Thin Provisioning Z 13