Sort of tangential to this discussion, but we elected to mirror a local physical drive and a SAN drive. When a SAN outage occurs, AIX issues an error report (errpt command), and the SAN side of the mirror goes stale, but the data is captured locally.
When the SAN connect is restored, AIX (5.2) resynchs the SAN disk to the up to date local disk.
Sometimes a belt and suspenders isn’t enough, and a piece of twine is all you have left to hang on to. Overall, the SAN is more robust when operational, but is subject to more frequent maintenance outages than local disk.
