Creating The Performance Read Cache, Adding Volumes, And Removing Volumes - IBM System Storage DS3000 Programming Manual

v Performance Modeling
v Locate
v View Associated Physical Components
v Add Drives (Capacity)
v Remove Drives (Capacity)
v Suspend
v Resume
v Delete
v Enabling/Disabling Performance Read Cache
v Change I/O Type
v Rename
Performance Read Cache restrictions
v Performance Read Cache is not supported on Enhanced FlashCopys (legacy) volumes and Enhanced
FlashCopy images.
v If you import or export base volumes that are Performance Read Cache enabled or disabled, the cached
data is not imported or exported.
v The maximum usable Performance Read Cache capacity on a storage subsystem is dependent on the
controller's primary cache capacity.
v When you create an Performance Read Cache, T10PI is automatically enabled if all the drives are
T10PI-capable and the T10PI premium feature is enabled. T10PI cannot be disabled on the Performance
Read Cache, nor can you add non-T10PI capable drives to a T10PI-enabled Performance Read Cache.
v You cannot remove the last drive in an Performance Read Cache without first deleting the Performance
Read Cache.
v Only one Performance Read Cache is supported per storage subsystem.
Creating the Performance Read Cache, adding volumes, and removing
volumes
Before you create the Performance Read Cache, make sure that suitable SSD drives are available on the
storage subsystem. You can achieve the best performance when the working set of the data fits in the
Performance Read Cache so that most host reads can be serviced from the lower latency solid state disks
instead of the higher latency hard drives (HDDs).
To create the Performance Read Cache run this command:
create performanceReadCache
userLabel="performanceReadCacheName"drives=(enclosureID1,drawerID1,slot
ID1 ... enclosureIDn,drawerIDn,slotIDn)[updateExistingVolumes=(TRUE
|FALSE)]
To use this command you need only to create a name for the SSD cache and identify the specific SSD
drives that you want to include in the cache. After you run the command, all of the volumes in the
storage subsystem can use the Performance Read Cache.
If you do not want all of the volumes in the storage subsystem to use the Performance Read Cache, set
the updateExistingVolumes parameter to FALSE. When you create the Performance Read Cache without
volumes, you can later assign specific volumes to the Performance Read Cache by running this command
for each volume that you want to add:
set volume ["volumeName"] performanceReadCacheEnabled=TRUE
You can assign standard volumes, Enhanced FlashCopy volumes, or consistency group Enhanced
FlashCopy volumes. You can assign only volume at a time to the Performance Read Cache.
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IBM System Storage DS3000, DS4000, and DS5000: Command Line Interface and Script Commands Programming Guide