cool stuff indeed ..so how does ALUA work ?

nice ..i guess we have to wait until October for ALUA aware powerpath.

see path management:
https://powerlink.emc.com/nsepn/webapps/btg548664833igtcuup4826/km/live1/en_US/Offering_Basics/FAQ/PL_CLARiiON_FLARE26_SWEnhancementsFAQs_C.pdf


LUN trespassing is gone...

ALUA is a "poor mans active/active" as Storagzilla (http://storagezilla.typepad.com/storagezilla) likes to put it. You will take a performance hit for accessing a lun using the SP that is not hosting the lun. Ok for low performance stuff but you are still better off paying for the redundant hardware.

yeah ..it would be good enough for my test/qa boxes that are single attached. So if i zone my test box with one hba to SPA and SPB what am i really gaining with ALUA ? If i am running PowerPath without license it handles failover on the storage processor side right now. I guess your system would not be spewing error messaging about lun trespassing ?

Exactly, with the one hba system the benefit is that the lun does not have to trespass, which can sometimes queue i/o if under heavy loads.