HP XP P9500 Storage - Manual (Page 51)

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 VLL 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 VLL 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:
Create LDEV function
Use the Create LDEV function to create a customized variable-sized volume. Use Virtual LUN to
create an open-systems volume.
You can also use the Create LDEV function to create a volume to be used as a system disk on either
a mainframe or an open system. A system disk is not available to hosts, command devices, pool
volumes, journal volumes, and so on. For more information, see
“Using a system disk” (page 62) .
The following depicts an example of creating customized volumes. First you delete FVs to create
free space. Then you can create one or more customized volumes of any size in that free space.
Creating an LDEV
Use this procedure to create one or more internal or external logical volumes (LDEVs) in a selected
storage system. You can create multiple LDEVs at once, for example, when you are setting up your
storage system. After the storage system is set up, you can add LDEVs as needed.
Before creating an LDEV in a selected storage system, free space may need to be created. Before
volumes are deleted to create free space, remove the LU paths to the open-system volumes. For
instructions on removing LU paths, see
“Deleting LU paths” (page 188) .
You can create LDEVs using any of the following tabs in Remote Web Console:
•
Parity Groups tab when selecting Parity Groups.
You can create multiple LDEVs in the specified free space by setting the necessary items
collectively. If multiple free spaces are in one parity group, the number of free spaces appears
Create LDEV function 51