I don't know the answer to this question, but I'm trying to find this out ...
We have two HP c7000 enclosures with Virtual Connect FlexFabric modules to connect to external Cisco Ethernet switches and Brocade FC switches. Both enclosures are fully loaded with 8x BL620c G7 blade servers running ESXi 4.1 Update 2.
Right now we are still able to completely evacuate an enclosure if we want to do maintenance (mainly firmware upgrades) on it, because we have stretched two clusters over both enclosures that each have not more than 50% of their capacity used.
However, given our current VM growth rate we will soon reach a point where this will be no longer possible (without purchasing and deploying a third enclosure). So, I'm currently testing and looking for ways to do an online Virtual Connect firmware upgrade without interrupting network and SAN connectivity. With all the redundancy that is in the enclosure this should be possible, and an HP engineer I lately talked to confirmed that this is indeed possible using HP's Virtual Connect Support Utility (VCSU), and he pointed me to its manual for instructions.
I remember that I already tried this method a while ago. I don't know the firmware and tool versions anymore that I did this test with, but it was not very successful. Although I followed the instructions given I noticed ping timeouts for up to 15 seconds during the upgrade process (I was pinging the hosts VMkernel address).
I just started a thread in the VMTN forums to get some input from others. Has anyone done this successfully? Is there anything to check and configure that is not obvious before trying this? Please share your experience by posting to the VMTN thread or leaving a comment here. Thanks!
Once I have found a working method I will of course update this post!
Update (2011-12-21): I found it ... Read about it in my next post!