If your in a bind, your server can spare the extra resources, and you’ve got a lot of mailboxes to move to a different database in a hurry for one reason or another, you will probably want to edit the “MSExchangeMailboxReplication.exe.config” file located in the “Bin” folder of your server’s installation directory to increase the performance of the Microsoft Exchange Mailbox Replication Service. For a complete listing of the variables and their options in the config file, check out this site.
One word of advice, just make sure you’re editing the actual variable at the very bottom of the file and not the part where it sets the definitions and default parameters.
Here are a few variables you will want to adjust to increase performance and then restart the MRS service (please note that these are the maximum permitted values so use at your own risk):
MaxMoveHistoryLength = "100" MaxActiveMovesPerSourceMDB = "100" MaxActiveMovesPerTargetMDB = "100" MaxActiveMovesPerSourceServer = "1000" MaxActiveMovesPerTargetServer = "1000" MaxTotalMovesPerMRS = "1000"
Other variables that look interesting but I didn’t mess with are:
MinBatchSize = "100" MinBatchSizeKB = "256"
NOTE: I did notice that once I amped up a lot of these values, I started noticing a substantially higher corrupted item count when moving messages between databases. Perhaps the values I had set were overloading the server a bit too much, so I set everything back to their default values except “MaxTotalMovesPerMRS = 1000” and the corrupted items problem seemed to go away but it still processed more than just two items at one time.