Exchange Throttling Policy for Exchange Migration
What is Exchange Throttling?
Exchange throttling is a control mechanism in on-premises Exchange servers designed to maintain stable server performance and prevent a single user or process from consuming too many resources. These throttling policies help distribute resources evenly so all users receive consistent access and the server continues to run efficiently. During migration, these limits can sometimes affect performance, when multiple mailboxes are migrated simultaneously, the throttling restrictions may slow down the process or trigger temporary errors if the allowed resource usage is exceeded.
To prevent migration issues and ensure a smooth process, it is recommended to create a dedicated throttling policy migration. This helps the migration run without affecting overall server performance, allowing mailboxes and data to migrate smoothly with reliable performance and zero downtime.
How to Avoid Exchange Server Throttling?
The EdbMails application is designed to migrate emails and other mailbox items in a granular manner, which helps prevent throttling issues during migration.
In addition, you can create a custom throttling policy with higher limits than the default settings, or even disable these limits entirely, and assign it to the user account used by EdbMails. This ensures that the migration runs smoothly without interruptions, while maintaining optimal server performance.
Steps to create Custom Throttling Policy in Exchange Management Shell (EMS)
- Launch Exchange Management Shell (EMS)
To increase the limits, first verify the current throttling policy by running the following command:
Command: Copy & Paste it on EMS
Get-ThrottlingPolicy | fl
To create a new throttling policy, run the following command:
Command: Copy & Paste it on EMS
New-ThrottlingPolicy <Name of the new throttling policy>
Example: New-ThrottlingPolicy EdbMailsPolicy
Throttling policy settings.
Ensure your backup or migration tasks are not limited by reconfiguring the new policy settings. You can disable the limits entirely by using $null or Unlimited values, or customize them as needed.
For Exchange Server 2010:
Command: Copy & Paste it on EMS
Set-ThrottlingPolicy EdbMailsPolicy -RCAMaxConcurrency $null -EWSMaxConcurrency $null -EWSMaxSubscriptions $null -CPAMaxConcurrency $null
For Exchange Server 2013 and newer:
Command: Copy & Paste it on EMS
Set-ThrottlingPolicy EdbMailsPolicy -RCAMaxConcurrency Unlimited -EWSMaxConcurrency Unlimited -EWSMaxSubscriptions Unlimited -CPAMaxConcurrency Unlimited -EwsCutoffBalance Unlimited -EwsMaxBurst Unlimited -EwsRechargeRate Unlimited
Note : Although the parameters mentioned above are essential for EdbMails Exchange migration, additional throttling policy limits can be modified. To learn more about adjusting throttling policies in Exchange 2010, 2013, 2016, and 2019, visit the Microsoft website.
To ensure that the new throttling policy takes effect, it must be assigned to specific accounts. Specifically, you need to set the throttling policy 'EdbMailsPolicy' for all the mailboxes that you want to migrate using the EdbMails software. Otherwise, the new throttling policy will not be utilized at all.
Use the following cmdlet to assign the newly created policy to the admin account.
Command: Copy & Paste it on EMS
Set-Mailbox "<mailbox name >" -ThrottlingPolicy EdbMailsPolicy
In place of <mailbox name>, enter the name or alias of the mailbox account utilized by the administrator.
To assign the throttling policy to all organization users, run the following cmdlet:
Command: Copy & Paste it on EMS
Set-ThrottlingPolicy “EdbMailsPolicy” -ThrottlingPolicyScope Organization
