I'm currently at the beginning of a Microsoft Exchange 2007 to 2010 mailbox migration project (~350 mailboxes -> 1.2TB), but I've hit some stumbling blocks. Every time I kick off a mini migration of 10-20 mailboxes from the Exchange 2007 server, the server's CPU resources go straight to 100% for hours and hours making the server practically unresponsive, dropping inbound mail, and disconnecting client sessions.
Old Exchange Environment: Single Exchange 2007 virtual machine with all roles
New Exchange Environment: 2 x Exchange 2010 virtual machine with all roles
Old Exchange Environment: 4 vCPUs, 32GB vRAM
New Exchange Environment: Each have 2 vCPU with 8GB vRAM
Are there any best practices that I can use to throttle CPU usage during batch migrations?
Or any other tips that other Experts have used to stabilise the migration process?