We approached this in a phased manner, connecting 2 x old FC switches to the existing 8Gbps ports on the compellent (Fault Domain A and Fault Domain B), then connected the new 16Gbps interfaces to new FC switches on new Fault Domain C and new Fault Domain D. We are only moving selected servers across to the new FC switches, and over the course of several change windows.
Some pointers if you need to do this.
- Initiator HBAs may need to be removed then re-created within the Compellent for the new fault domains to be registered
- A reboot of the Dell Compellent is required after doing this, to remove the HBA records from the old Fault Domain, otherwise the paths show as degraded
It seems Compellent didn't think about the possiblity of migrating an initiator HBA from one Fault Domain to the other live. It seems the Compellent does its garbage cleanup after a reboot, but you probably don't want to be constantly rebooting the compellent storage if possible.
I'm awaiting further feedback from Dell, perhaps there are some advanced commands or utilities which would allow me to alter the Fault Domain member initiators... we will see.
Suggestions/recommendations on this are welcome and appreciated.