If you are migrating mailboxes from Groupwise to on-premise Exchange 2010 SP1, you will want to setup a throttling policy on Exchange 2010 SP1 that is almost identical to the typical throttling settings used for Blackberry and/or Cisco Unity.
I typically recommend not setting any of the throttling values to unlimited. This is a bit more restrictive than the suggestions made by the Blackberry and/or Cisco Unity settings.
The most important throttling value we need to increase for Quest's Groupwise Migrator is the RCAPercentTimeInAD. The telltale sign are throttling event logs on the Exchange server and see-saw network/cpu usage on the migration workstation. The Address Book service seems to receive quite a bit of traffic from the Groupwise migration tools due to user account look ups.
On most of my migrations, I ended up using a value of 200 for RCAPercentTimeInAD. I have yet to encounter a server that required value higher than 200.
Thankfully, you can apply this new policy on the user account that acts as the go-between Exchange and Groupwise. Typically, it is called something like GWMigrate.
Additionally, you can also apply this new policy on the migration workstation's computer account. Typically, it is called something like GWMigrateServer.
Using that server name and user name as an example, this is what you would execute with Powershell on the Exchange server:
New-ThrottlingPolicy "Groupwise Throttling Policy" -RCAPercentTimeInAD 200
$b = Get-ThrottlingPolicy "Groupwise Throttling Policy";
Set-Mailbox GWMigrateServer$ -ThrottlingPolicy $b;
Set-Mailbox GWMigrate -ThrottlingPolicy $b;
After setting those values, you will need to stop and restart the Exchange Throttling services for the updated settings to take effect.
