When using an A/A array to boot from a SAN, complete the following steps in the order presented:
Configure SAN boot LUNs with the lowest host target id. For example, target id 0, 1.
Encapsulate the root disk (SAN LUN) into VxVM.
Mirror the encapsulated root disk to another LUN on the same or different enclosure.
Create boot aliases/sequence so that server will boot from an alternate path if the primary boot path is not available.
When using A/P, A/P-F, and ALUA arrays to boot from a SAN, the following additional best practices need to be applied.
If the SAN Boot LUN and its mirror are on the same enclosure, they should have the same default owner (A/P array) or optimized path (ALUA) on the same controller. Otherwise, there are issues with "mirroring" the SAN boot LUN.
Boot aliases/sequence should be configured on the paths of the array controller which is the LUN owner (A/P and A/PF ) and optimized path (ALUA) for the SAN boot LUNs and its mirror.