I just had to dig this up for myself. I had a domain where five VNXs had been retired, and I had not removed them from the domain before they were dismantled.  For the record, the best thing *is* to remove them from the domain before shutting them down.  I came up with a naviseccli command that did the trick.  You direct the command at the master of the domain and tell it the IP that you want to remove. Removing one SP removed the whole array.  naviseccli -Address  [IP of master] -User [administrator or other admin account] -Password [password for that account] -Scope 0 domain -remove [IP of one SP of the array to be removed]  This came from a post in the Clariion forum here, from a number of years ago, but it worked for me.
We recently decommissioned a VNX and in Unisphere it now shows up as a pair of non-validated ip-addresses. does anyone know how to remove this VNX from the domain? I've tried engineering mode, but that doesn't help.
Unable to remove retired VNX from domain