HP XP Racks - Manual (Page 43)

Virtualizing storage capacity
This module describes how to virtualize storage capacity.
About virtualizing storage capacity
HP StorageWorks P9000 Thin Provisioning (THP) provides virtual volumes to a host and allocates the
actual capacity from a THP pool when a host makes a write request. By using THP pools, you can
allocate more capacity to a host than that allowed by the actual physical configuration of the storage
system.
THP pools provide the following advantages:
• You can reduce system setup and operational costs.
• You can use resources more efficiently.
• You can distribute workload equally among volumes.
Smart Tiers (Smart) improves the THP pools storage performance. If you create a pool that combines
volumes with different cost performance, such as combining higher cost, high-speed volumes (SSD or
SAS) with inexpensive low-speed volumes (SATA), Smart rearranges the volume load automatically.
This rearrangement is performed depending on the I/O load; high-load pages are allocated to
high-speed volumes, and low-load pages are allocated to low-speed volumes.
You can create virtual volumes (THP/Smart volumes) from physical volumes that are grouped into
THP/Smart pools. You can then allocate those virtual volumes to hosts.
In the illustration below, note that the volumes used to create the THP/Smart pool are called THP/
Smart pool volumes. The THP/Smart pool is then used to provide capacity as needed to allocated
THP/Smart volumes.
THP/Smart pools management functions
THP/Smart pools management covers the following operations:
• Creating THP/Smart pools allows Device Manager to automatically select a volume and then
create THP/Smart pools based on user-specified conditions. When creating THP/Smart pools,
users can specify threshold values for excess usage rate and reservation rate. For Smart pools,
users can specify options related to re-arrangement. When an external volume is included in a
User Guide 43