ibm ds4700 / logical drive not on preferred path

a ibm ds4700 with four exp 810 units lost it`s preferred path setting for one controller /some logical drives. consequences : there were some machines with non-redundant paths connected to the san – these machines lost their mounted luns.(datastore for a mail machine, datastore for a fileserver with 14TB…) first i changed on the fibre channel switch fabric the zoneing to the healthy controller and remounted the drives to get the server systems back on production. after some research i seems to be clear that the solution is just only to map the logical drives back to the preferred controller/path … *sigh you can change the controller settings for the logical drives under production scenario. learned: do *all* fc/san connections redundant – don`t save money on your fibrechannel san design … 🙂

message on the storage manager / recovery guru : Logical Drive Not On Preferred Path