Disclaimer: I haven’t done a Windows-based CLARiiON host-attach activity in about 4 or 5 years. And it’s been a bit longer than that since I did boot from SAN configurations. So you can make of this what you will. We’ve been building a Windows 2008 R2 Boot from SAN cluster lately. We got to the point where we were ready to add the 60+ LUNs that the cluster would use. The initial configuration had 3 hosts in 3 storage groups with their respective boot LUNs. I had initially thought that I’d just create another Storage Group for the cluster’s volumes and add the 3 hosts to that. All the time I was trying to remember the rule about multiple hosts or multiple LUNs in a Storage Group. And of course I remembered incorrectly.
To get around this issue, I had to add each LUN (there are about 67 of them) to each Storage Group for the cluster nodes. And ensure that they had consistent host IDs across the Storage Groups. Which has worked fine, but isn’t, as Unisphere points out, recommended. There’s also an issue with the number of LUNs I can put in a Consistency Group (32) – but that’s a story for another time.