It all depends on how they're mapped. If Cluster A hosts are mapped in the same initiator group (this depends on your storage vendor), then it's possible to remove Cluster A and Cluster B hosts at the same time. If hosts are mapped by Cluster or individually, the operation is a bit more safe.
Just be clear with the storage team and list the initiators you want unmapped from particular LUNs.
- Mike
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Mike Brown
VMware, Cisco Data Center, and NetApp dude
Consulting Engineer
Twitter: @VirtuallyMikeB
Blog: http://VirtuallyMikeBrown.com
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