How To: Create an Exchange 2013 Throttling Policy for Migration.
In order to achieve the best throughput, a new Exchange throttling policy must be applied to both the ODM Exchange admin account(s) as well as the end-user mailboxes that are being migrated. These steps are valid for when Exchange 2013 is either the Source or the Target:
1. Open the Exchange 2013 Management Shell.
2. Issue the following cmdlets:
New-ThrottlingPolicy ODM_Policy
Set-ThrottlingPolicy ODM_Policy -RCAMaxConcurrency Unlimited -EWSMaxConcurrency Unlimited -EWSMaxSubscriptions Unlimited -CPAMaxConcurrency Unlimited -EwsCutoffBalance Unlimited -EwsMaxBurst Unlimited -EwsRechargeRate Unlimited
Get-Mailbox -ResultSize unlimited | Set-Mailbox -ThrottlingPolicy ODM_Policy
3. For this new throttling policy to take effect immediately, you would need to perform either an "iisreset" from a Command Prompt, or Recycle the "MSExchangeServicesAppPool" in the IIS Management Console on the Exchange server(s) that are hosting the EWS URL that was entered into the ODM connection settings.
Note: Once the migration project is complete, you may want to remove the ODM_Policy from all users by running the following cmdlet in an Exchange Management Shell to restore normal Exchange functionality:
Get-Mailbox -ResultSize unlimited | Remove-ThrottlingPolicy ODM_Policy
For more generic information on Exchange Throttling Policies have a look at the following Microsoft Technet article:
https://technet.microsoft.com/en-us/library/jj150503(v=exchg.150).aspx
Note:
Depending on the exact version of Exchange being used, this throttling
policy may need to be applied to either the Exchange migration admin
user, and/or to the end-user mailbox that is migrating. See the
following Microsoft MSDN article that explains who the throttling
policy counts against, depending on the exact version of Exchange in
use:
https://msdn.microsoft.com/en-us/library/office/jj945066(v=exchg.150).aspx#Anchor_2
