From: Jay Soffian [mailto:jay@cimedia.com] We are going to be adding an additional FC shelf to our clustered F740's. Obviously, the safe way to do this is to halt both 740's, attach the A & B loops, then bring both filers back up.

But, what I was wonder was, would it be possible to:

• Attach the B-loop first.
• Have the B-Loop Filer take over all th shelves (including

the new shelf).

• Attach the A-Loop.
• Give back the shelves to the A-Loop filer.

I don't think we'll do this as we're only talking about about maybe 2 minutes of downtime vs 30 seconds, but I was wondering if this is a feasible thing to do.

Adding a disk shelf requires the FCAL cable to be unplugged while that shelf is being rewired. This requires the owning node to be HALTed at the time. It is possible to keep one member of the cluster alive during shelf rewiring. The approach is to HALT one node, failover to the other node, wire up the first node's A loop, and then bring that first node back to life. Then repeat the process, failing over and rewiring in the opposite direction.