if host is connected to  SPA and SPB, that LUN will simply trespass to SPA and serviced there.  I don't remember how ALUA changes things becuase it can service I/O from the alternative SP through the internal CMI bus but i think it only happens for so many I/O before it actually trespasses the LUN.
Hi guys  I'm new in the emc community. I have a question about the vnx sp failover (LUN trespass). If I have a host with two HBA connected. (one to each SP)  I'm right if I say that when a host HBA, a  cable or a SP HBA fails the host lose the connection to all the LUN that are owned by the SP that something of the above things failed ?  My interpretation was always that only if an SP completly fails the LUN will be trespassed to the other SP. Hopefully someone can clearify this for me.  Thanks in advanced ! Cheers  Mark
SP failover direct attached Hosts