Exchange 2007 to Exchange 2010 cross forest simultaneous mailbox move limits

Question

Hi All, 
I am testing the throughput of mailbox moves from Exchange 2007 to Exchange 2010 cross forest. Single mailbox moves seem to be quite fast and I am not concerned about network, disk IO or server resource limitations, however I have not tested multiple simultaneous
mailbox moves to determine what the Exchange limitations are. If anyone could identify the limitations of the items below it would be much appreciated: 
Limit of Exchange 2007 simultaneous mailbox moves per database
Limit of Exchange 2007 simultaneous mailbox moves per Mailbox server
Limit of Exchange 2007 simultaneous mailbox moves per CAS server
Limit of Exchange 2010 simultaneous mailbox moves per database
Limit of Exchange 2010 simultaneous mailbox moves per Mailbox server
Limit of Exchange 2010 simultaneous mailbox moves per CAS server
Any other Exchange 2007 or 2010 hard coded limits
Thanks in advance. 
Michael.

Answer 1

My usual answer to this question is that Microsoft set these limits for a reason.  Increasing them may not offer you much in the way of benefits if you end up slamming the server.  I generally recommend that you leave them alone.
I have had occasional opportunities to change these constraints, most notably back during a migration to Exchange 2003 and international mailbox moves (Asia to U.S.) where the limiting factor was network latency.  I was able to increase the number of
concurrent threads to 16 from the default 2 and there was still available bandwidth because the process was limited by the latency. 
Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."