Create volume group
You use a volume group to create one or more volumes that are accessible to the host. A volume group is a container for volumes with shared characteristics such as RAID level and capacity.
With larger capacity drives and the ability to distribute volumes across controllers, creating more than one volume per volume group is a good way to make use of your storage capacity and to protect your data.
Follow these guidelines when you create a volume group.
You need at least one unassigned drive.
Limits exist as to how much drive capacity you can have in a single volume group. These limits vary according to your host type.
To enable shelf/drawer loss protection, you must create a volume group that uses drives located in at least three shelves or drawers, unless you are using RAID 1, where two shelves/drawers is the minimum.
Review how your choice of RAID level affects the resulting capacity of the volume group.
If you select RAID 1, you must add two drives at a time to make sure that a mirrored pair is selected. Mirroring and striping (known as RAID 10 or RAID 1+0) is achieved when four or more drives are selected.
If you select RAID 5, you must add a minimum of three drives to create the volume group.
If you select RAID 6, you must add a minimum of five drives to create the volume group.