HP XP P9500 Storage - Manual (Page 96)

levels can coexist in one pool. If you specify the level of the tiering policy, THP V-VOLs to which
the same policy is set are grouped.
•
All is the default tiering level. In this case, data is stored to all of the tiers.
•
When a tier is added to the pool after setting the tiering level on a THP V-VOL, the THP V-VOL
is relocated according to the new tier lineup.
For example, if you set the tiering policy to level 5, the data is always allocated to the tier of
the low I/O speed. If the pool has two tiers, data is stored in tier 2. If a new tier is added,
the number of tiers becomes three and if the new tier is the lowest tier, relocation will be
performed to move data into tier 3.
Example of adding a tier
If the added pool-VOLs is a different media type, then a new tier is created in the pool. The tier is
added to the appropriate position according to its performance. The following figure illustrates
adding a tier.
Example of deleting a tier
If a tier no longer has any pool-VOLs when you delete them, the tier is deleted from the pool. The
following figure illustrates deleting a tier.
For more information about tiering policy and groups, see (page 96) .
Tiering policy levels
Note Number of tiers in pool Tiering policy
3 tiers 2 tiers 1 tier
Default value. Data is
stored in all tiers. All tiers All tiers All tiers All
Data is always stored
in the high speed tier. Tier 1 Tier 1 All tiers* Level 1
N/A Tier 1 and Tier 2 All tiers* All tiers* Level 2
Tier 2 All tiers* All tiers* Level 3
Tier 2 and Tier 3 All tiers* All tiers* Level 4
Data is always stored
in the low speed tier. Tier 3 Tier 2 All tiers* Level 5
*Data is stored in all tiers as in the case of All specified.
Viewing the tiering policy in the performance graph
You can view the frequency distribution graph of the pool by selecting either the level of the tiering
policy or the entire pool on the performance graph in the View Tier Properties window.
96 Configuring thin provisioning