I'm running an SBS 2003 to 2011 migration and the "Move Mailbox" step is taking a really, really long time.
Both servers are VM's on an 2x 4-core IBM x3500 box with 24GB RAM and SAS disks (RAID5). Both VM's have 4 vCPU's and 4gb/12gb RAM (2003/2011).
There are only 15 mailboxes, though they are huge - 11gb down to 1gb, avg size of 4gb per box. Total info store size is around 65gb.
I am running this as a test migration, so I have snapshots on both servers (allowing me to roll back if it tanks, fix any errors, then continue) - again, this is not live, and the 2 servers can only see each other in the vSwitch.
Is this normal? Would an offline defrag on the source server make any difference? Does this seem like a problem on the source (sbs2003) or dest (sbs2011) server?