We've recently completed a legacy storage to FAS3140 (rebrand) Exchange migration. We had consultant help every step of the way, and the correct procedure in their experiece is to remove ALL vestiges of MPIO support from your legacy vendor, but do not install the NetApp DSM for MPIO until your migration is completed.
We ran for two weeks with single-intiator-single-target zoning from both arrays while we migrated. We installed SnapDrive and SnapManager for Exchange, but not MPIO, and used SME to perform the migratition.
I am at a loss for the proper NOW and KB articles, but I believe that multiple MPIO installations are not supported by any of the vendors we were dealing with. It was just a risk we need to accomplish the move.
Once Netapp DSM for MPIO was installed, we brought the cluster completely down, rezoned using single-initiator-zoning to all target ports, and booted without any trouble from the MS cluster. It just sort of worked and made us happy.
I hope this helps. I will try to find the supporting documentation.
That certainly sounds as though it will work and I had been giving that some thought.
The problem is that there is no appetite on the customer end for a single path to each storage controller for the period of the migration. If that is the only way to do it, then I guess they'll have to bite the bullet.
Tomorrow I am going to setup a test server, add Dynapath, connect it to some new luns on the old controller, then remove Dynapath and install our MPIO software. I'm hoping it will handle the mutiple paths.
Is anyone aware if this might work. The storage is a 4 or 5 year old IPstorage box.
Then I want to connect to NetApp LUNs with this test machine and see how it handles i/o between them.
I don't see any problems with running Dynapath with NetApp LUNs. Multipathing is Multipathing, so long as it's not tied to a vendor. I don't think NetApp MPIO drivers would do a good job of managing a legacy SAN paths, but Dynapath should be okay at managing the NetApp. You may need to do some customising in regards to which path goes to the correct cluster controller, so the pathing may not be the most ideal or best, but it should at least work.
Would the customer be comfortable with a single path to one SAN and multiple paths to the other? This might work better from the MPIO driver side of things.
I guess it's a decision between MPIO with less support, or greater support with less path protection.