Chapter 9. Advanced features for storage efficiency 445
Normal Easy Tier migration speed is 12 GB every 5 minutes for all functions, except cold
demote, which is 1 GB every 10 minutes.
Accelerated mode allows an Easy Tier migration speed of 48 GB every 5 minutes with no limit
on cold demotes and no support for warm demotes.
You enable Easy Tier accelerated mode from the command line by using chsystem
-easytieracceleration on/off.
9.2.9 Easy Tier operating modes
The IBM Storwize V5000 Gen2 offers the following operating modes for Easy Tier:
Easy Tier: Off
Easy Tier can be turned off. No statistics are recorded and no extents are moved.
Easy Tier: On
When the Easy Tier function is turned on, Easy Tier measures the I/O activity for all
extents. With a multi-tiered pool, the extents are migrated dynamically by the Easy Tier
processes to achieve the best performance. The movement is transparent to the host
server and applications.
A statistic summary file is created. This file can be off-loaded and analyzed with the IBM
Storage Tier Advisory Tool, as described in 9.2.16, “IBM Storage Tier Advisor Tool” on
page 465. Easy Tier can be turned on for any single-tiered or multi-tiered pool, but its
functionality will differ on each of them.
Easy Tier: Measured mode
When Easy Tier is in measured mode, Easy Tier measures the I/O activity for all extents
but it does not move any extents within the storage pool. A statistics summary file is
created. This file can be off-loaded from the IBM Storwize V5000 Gen2. This file can be
analyzed with the IBM Storage Tier Advisory Tool. This analysis shows the workload
benefits of adding or removing different drive classes from a pool before any hardware is
acquired. No license is required to set Easy Tier to measured mode.
Easy Tier: Auto
Auto mode is the operating mode default. If Easy Tier is set to auto for a single-tiered
storage pool, Easy Tier is set to off for all volumes inside the storage pool and no extents
are moved. If Easy Tier is set to auto for a multi-tiered storage pool, the Easy Tier status
becomes active and Easy Tier is set to on for all volumes inside the storage pool and the
extents are migrated dynamically by the Easy Tier process. However, the extents are not
migrated if the Easy Tier function is not licensed.
Note: Accelerated mode is not intended for day-to-day Easy Tier traffic. Turn on
accelerated mode when necessary. Because Easy Tier accelerated mode can increase the
workload on the system temporarily, use Easy Tier accelerated mode during periods of
lower system activity.
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