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. Report LUNs is supported by LUN 0, so the Lenovo Storage V series system can detect all LUNs.
In the event that a 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 Lenovo Storage V series 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 Lenovo Storage V series system must use open emulation. All LUNs with open emulation use a standard 512 byte block size.
The HDS Lightning system can only have certain sized LUs that are defined. These LUs can be expanded by merging 2 - 36 of these LUs 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 have the option to make it a command LUN. Command LUNs support in-band configuration commands, but not I/O. Therefore, you cannot map command LUNs to the Lenovo Storage V series system.