HP XP7 Storage - Manual (Page 90)

The following figure shows an example of data allocation when setting the tiering policy to Level1(1)
(see Level1(1) in
“Tiering policy levels” (page 91) ). In this case, pages in the THP V-VOL are
relocated to tier 1, and are not relocated to other tiers.
Setting tiering policy on a THP V-VOL
The setting of a tiering policy for a THP V-VOL is optional. If one is not selected, the default is the
All(0) tiering policy level. The available levels are listed in
“Tiering policy levels” (page 91) ). THP
V-VOLs of different tiering policies can coexist in one pool. If you specify the level of the tiering
policy, THP V-VOLs with the policy are grouped together.
•
All(0) is the default policy. In this case, data is stored to all of the tiers.
•
When a tier is added to the pool after setting the tiering policy 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.
90 Configuring thin provisioning