The tier range, frequency distribution, and used capacity are displayed per tiering policy: existing
tier level All(0), Level1(1) through Level5(5) and Level6(6) to Level31(31).
Tiering policy expansion
In the current release, the tiering policy concept has been expanded to provide new options:
• Custom policies. You can define up to 26 new policies (Level6(6) - Level31(31)) in addition
to the existing six (All(0), Level1(1), Level2(2), Level3(3), Level4(4), and Level5(5)). See “Setting
tiering policy on a THP V-VOL” (page 99).
A custom policy can be set for a THP V-VOL when it is created and changed, if necessary,
after creation.
NOTE: Custom policies cannot be renamed.
• Smart Tiers performs relocation while calculating page allocation based on the tiering policy
setting of all THP V-VOLs that have the same tiering policy in each pool.
• Max(%) and Min(%) parameters. When a tiering policy is created, 4 types of parameters can
be set: Tier1 Max and Tier 1 Min, Tier 3 Max and Tier 3 Min. Each parameter setting is a
ratio that corresponds to the total capacity of the allocated area of THP V-VOLs that have the
same tiering policy set for a pool. See “Tiering policy examples” (page 98).
Tier1 and Tier3 parameter settings can also limit the capacity for all volumes in a configuration
that contain multiple THP V-VOLs that have the same intended use. These settings can prevent
conditions such as the following from occurring.
◦ Excess allocation of SSD capacity for unimportant applications.
◦ Degradation in average response time for high performance operations.
Tiering policy examples
The following figure shows the parameter settings Tier1 Max=40%, Tier1 Min=20%, Tier3
Max=40%, and Tier3 Min=20% for a THP V-VOL with a Level6(6) setting when the initial allocated
capacity of is 100GB.
The following figure shows an example of data allocation when the default tiering policy level
All(0) is specified. Pages in the THP V-VOL are relocated to any tier.
98 Configuring thin provisioning
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