Hello,   Yes it is a safe to upgrade.  The firmware upgrade process will upgrade the software on both controllers.  Then restart the passive controller.  When that completes is will faillover the active to the passive.  Finally the old active controller will be restarted to complete the process.   The firmware upgrade installation document has more info and what intermediate firmware you will have to install first.  You won't be able to go directly to the latest firmware from 7.x.  Regards, Don   
Hello, I want to upgrade the firmware of the controllers on our equillogic PS6100. We're currently running V.7.1.2. Is it safe to upgrade this to a new firmware without the equillogic going down? Or do both controllers go down?   Thanks in advance,   Bjorn
EqualLogic PS6100 firmware upgrade question