IBM DS8882F, Введение и руководство по планированию

Страница: 51 / 164

capacity. However, a reduction in the size of the extent pool can cause the
allocatable physical capacity to become less than the allocated physical capacity in
some cases.
For example, if the user requests that one of the ranks in an extent pool be
depopulated, the data on that rank are moved to the remaining ranks in the pool
causing the rank to become not allocated and removed from the pool. The user is
advised to inspect the limits and threshold on the extent pool following any
changes to the size of the extent pool to ensure that the specified values are still
consistent with the user’s intentions.
IBM Easy Tier
Easy Tier is an optional feature that is provided at no cost. It can greatly increase
the performance of your system by ensuring frequently accessed data is put on
faster storage. Its capabilities include manual volume capacity rebalance, auto
performance rebalancing in homogeneous pools, hot spot management, rank
depopulation, manual volume migration, and thin provisioning support (ESE
volumes only).
Easy Tier features help you to effectively manage your system health, storage
performance, and storage capacity automatically. Easy Tier uses system
configuration and workload analysis with warm demotion to achieve effective
overall system health. Simultaneously, data promotion and auto-rebalancing
address performance while cold demotion works to address capacity.
Easy Tier data in memory persists in local storage or storage in the peer server,
ensuring the Easy Tier configurations are available at failover, cold start, or Easy
Tier restart.
The Easy Tier Heat Map Transfer utility replicates Easy Tier primary storage
workload learning results to secondary storage sites, synchronizing performance
characteristics across all storage systems. In the event of data recovery, storage
system performance is not sacrificed.
You can also use Easy Tier to help with the management of your ESE thin
provisioning on fixed block (FB) or count key data (CKD) volumes.
An additional feature provides the capability for you to use Easy Tier manual
processing for thin provisioning. Rank depopulation is supported on ranks with
ESE volumes allocated (extent space-efficient) or auxiliary volumes.
Use the capabilities of Easy Tier to support:
Drive classes
The following drive classes are available, in order from highest to lowest
performance.
Flash Tier 0 drives
The highest performance drives, which provide high I/O
throughput and low latency.
Flash Tier 1 drives
The first tier of high capacity drives.
Flash Tier 2 drives
The second tier of high capacity drives.
Chapter 3. Data management features
41