Hi,
Windows is writing a serial to the LUNs, it's not the Netapp LUN serial.
1) create the snapmirror, let it be in sync
1a) stop the Windows cluster and make sure that's not starting if server is rebooted
2) shutdown the server
3) unmap the LUNs
4) update, quiesce and break the snapmirror
5) map the LUNs on the destination filer
6) start the server
7) rediscover the disk in windows
You don't need 7MTT or SnapDrive for this.
Just pure comandline 🙂