The ASL reports information about the multipathing configuration to the DDL as an Active/Active (A/A), ALUA, or an Active/Passive Concurrent (A/P-C) disk array type.
There are multiple active paths to a storage system, and simultaneous I/O is supported on each path. If a path fails, I/O is distributed across the remaining paths.
An A/P-C array is a variant of the A/P array type that supports concurrent I/O and load balancing by having multiple primary paths to LUNs. Failover to the secondary (passive) path occurs only if all the active primary paths fail.
A LUN in an ALUA-enabled array can be accessed through both controllers, by using optimized and non-optimized paths. The array notifies the host of path options, their current state, and state changes. Using this information, the host can determine which paths are optimized. Failover to the non-optimized path occurs only if all the optimized paths fail.
For more information about system management, see the Veritas Volume Manager Administrator’s Guide.