I'm not sure what the restricted access would be... but being unbalanced means that only a single controller is active and that all LUNS are being serviced from the one controller. Rebalancing moves the servicing of the LUNs from the non-active controller back over to it and makes it active again.  Rebalances typically take anywhere from 5-15 seconds depending on activity but if you've followed best practices with server HBA settings, etc. then you are providing up to 60 seconds of "paused IO" to occur, which is what happens to the LUNs that are moving back over to their original controller.
We had some power work done at the site, and when I log into the SC8000 admin pages it now states the controllers need to be rebalanced, but also states that system access will be restricted. Unfortunately it does not specify WHAT is being restricted... just admin console access? will all my servers lose access to their LUNs? i have to schedule something that would cause loss of access to the SAN data.. but if I cant get into the admin page for an hour, thats no big deal. Couldnt find anything in a doc stating what exactly will be lost for connectivity... tried the admin docs, upgrade guides, etc. Yes I know they should be balanced. But I don't know the impact starting that process will have in my environment... Any help from someone that has done this already or knows whats going to happen? Thanks! -=RB
Does re-balancing SC8000's result in an outage?