Hi
We have been using a HP EVA 4000 fc-san now for 5 years, without having any problems, but the time is here to invest in a new san. We have decided for a EVA 6400 fc-san (with iSCSI), and intend to migrate all existing data over to the new system.
We have about 5 ESX hosts and 80 VMs. We have 6 shared storage LUNs for the ESX hosts, and use about 50 Raw Device Mapping (RDM)(physical).
The main reason for buying a new EVA, is the ability to use 90-days migration license for "continous access". This enables the old EVA to mirror (one way, old => new) LUNs over to a new EVA. I dont know wheter WWN og LUN-number are migrated. Then i just power down the whole vmware farm, stop the mirror (makes the new EVA read-write) and connects the vmware-farm to the new fabric (already zoned).
So over to the main problem:
I guess the shared storage reference by data on the disks, partition ID's or something, so i don't think these will make problems
I need to know how a RDM are referenced, are they referenced by "some data on the disk", by WWN, by LUN-number or something else?
Another solution is to use storage vmotion, by connection the ESX-servers to BOTH FC-fabrics, creating new shared storage on the new san, and moving server by server. I then have to mirror the RDMs, and re-connect them after the migration of each VM.
Two important aspects you may want to ask yourself are "how quickly do I want to move" and "do I want to rebalance what VM's are in what datastores." The answers to these two questions will largely in part drive which migration approach makes the most sense for you.
RDMs are referenced by SCSI Page 80/83 serial #.
--Matt
VCP, vExpert, Unix Geek