Logical unit (LU) configuration for HDS Lightning supports both RAID 1 and RAID 5 arrays.
The HDS Lightning system can have up to 8192 LUs defined; however, only 256 LUs can be mapped to a single port. The report LUNs command is supported by LUN 0, so the Storwize V5000 system can detect all LUNs.
If LUN 0 is not configured, the HDS Lightning system presents a pseudo-LUN at LUN 0. The inquiry data for this pseudo-LUN slightly differs from the inquiry data of normal LUNs. The difference allows the Storwize V5000 system to recognize the pseudo-LUN and exclude it from I/O. The pseudo LUN can accept the report LUNs command.
The HDS Lightning system supports both open-mode attachment and IBM zSeries attachment. The emulation mode is set when the LU is defined. All LUNs that are presented to the Storwize V5000 system must use open emulation. All LUNs with open emulation use a standard 512-byte block size.
The HDS Lightning system can have only certain sized LUs that are defined. These LUs can be expanded by merging 2 - 36 of these LUs by using the Logical Unit Size Expansion (LUSE) feature. They can also be made into several smaller virtual LUNs by using the Virtual LVI/LUN feature.
When an LU is mapped to a host, you can make it a command LUN. Command LUNs support in-band configuration commands, but not I/O. Therefore, you cannot map command LUNs to the Storwize V5000 system.