Configuring Volumes In A Parity Group; Configuration Of Interleaved Parity Group - HP XP7 User Manual

Configuring volumes in a parity group

For RAID 5 (7D+1P), RAID 6 (6D+2P), or RAID 6 (14D+2P) a maximum of 2,048 fixed-size volumes
(FVs) and a certain amount of free space are available in one parity group. For other RAID levels,
a maximum of 1,024 FVs and a certain amount of free space are available in one parity group.
Each parity group has the same configuration, and is assigned the same FVs of the same size and
RAID level.
The Virtual LVI functions of Delete LDEVs and Create LDEVs are performed on each parity group.
Parity groups are also separated from each other by boundary limitations. Therefore, you cannot
define a volume across two or more parity groups beyond these boundaries.
As the result of the Virtual LVI operations, a parity group contains FVs, CVs, and free spaces that
are delimited in logical cylinders. Sequential free spaces are combined into a single free space.
The following depicts an example of configuring volumes in a parity group:

Configuration of interleaved parity group

If RAID configurations are RAID1 (2D+2D) or RAID5 (7D+1P), the interleaved parity group can be
created by concatenation of multiple parity groups. RAID configurations and the number that can
be concatenated are as follows:
RAID configuration
RAID1 (2D+2D)
RAID5 (7D+1P)
When concatenating parity groups, data in LDEVs that are FV or CV are dispersedly allocated
between the interleaved parity groups Therefore, loads are dispersed because of the parity group
concatenation, so that the performance of LDEV is improved.
The capacity of the created LDEVs are managed by each of the parity groups that are in the
interleaved parity group. The maximum capacity of an LDEV is the same as the capacity of the
interleaved parity group.
NOTE: Even if the parity groups are concatenated, the total capacity of the interleaved parity
group will not be of large capacity.
See the examples below:
Creating the interleaved parity group by concatenating of parity groups of PG1- 1 and PG1-2.
Creating LDEVs in each parity group that are in the interleaved parity group.
◦
LDEV 1 in PG1- 1
◦
LDEV 2 in PG1-2
2 concatenating
Available
Available
4 concatenating
Not Available
Available
Configuration of interleaved parity group 39