Logical Unit

Logical volumes are created from the shared storage pool to which they belongs. Logical units can be of different types, but all are files in the pool. The hardware management console (HMC) supports the following types of logical units :

• VirtualIO_Disk : A disk logical unit simulates a disk and is mapped to a client partition.
• VirtualIO_Image : An Image logical unit is a part of image management and can be used to rapidly deploy client logical partitions. An image logical unit contains the operating system image. Image logical units can not directly be mapped to a client logical partition.

A logical unit can be created as either with a THICK or a THIN provisioning capability.

• THIN : THIN logical units might present a much larger image than the current or actual physical use. These logical units are not fully backed by physical storage if the blocks are not in actual use.
• THICK : THICK logical units do not allow to commit beyond the available physical storage. These logical units are fully backed by physical storage, irrespective of the actual usage.

Logical units also support cloning. The HMC provides option to perform linked clone of logical units.