Impact of Exchange throttling policy on EdbMails

This article explains throttling and how the Exchange throttling policy impacts the functionality of EdbMails. Additionally, it also describes how to control Exchange throttling policies

What is throttling?

Throttling is a reactive response against over utilization of system resources that may affect service reliability and functionality. It imposes a limit on the number of concurrent call requests that can be executed at the same time.

How does Exchange throttling policy affect EdbMails?

Exchange throttling policy affects the backup and migration speed and displays errors during the operation with EdbMails. Throttling is one of the reasons for the errors related to insufficient impersonation rights that may appear frequently.

How to avoid throttling issues?

Create a custom throttling policy with limits higher than the default ones or even disable these limits and assign it to the user account used in the EdbMails application during migration.

Steps to create a custom throttling policy

You can create custom throttling policies with limits greater than the default in an on-premises Exchange environment. You can also disable these restrictions completely if necessary. To perform the backup and/or migration operation, you can assign this policy to the user account used in EdbMails. However, proceed with caution and ensure that your Exchange servers can handle the increased number of concurrent queries. To customize the throttling policy, follow the below steps.

1. Open Exchange Management Shell (EMS).
2. Run the following cmdlet to check current throttling
   
   

   Get-ThrottlingPolicy | fl

3. Run the following cmdlet to create a new throttling policy
   
   

   New-ThrottlingPolicy <Throttling_Policy_Name>

   For example:

   New-ThrottlingPolicy EdbMailsPolicy

4. The New policy settings have to be reconfigured in a way that does not hinder the backup or migration tasks. Use $null or Unlimited values to use custom values or to disable the limitation.

   1. For Exchange Server 2010 version:

      Set-ThrottlingPolicyCodeTwoPolicy -RCAMaxConcurrency $null -EWSMaxConcurrency $null-EWSMaxSubscriptions $null -CPAMaxConcurrency $null

   2. For Exchange Server 2013 and later versions:

      Set-ThrottlingPolicyCodeTwoPolicy -RCAMaxConcurrency Unlimited -EWSMaxConcurrency Unlimited-EWSMaxSubscriptions Unlimited -CPAMaxConcurrency Unlimited -EwsCutoffBalanceUnlimited -EwsMaxBurst Unlimited -EwsRechargeRate Unlimited

      If you want to know how to change the throttling policies in Exchange 2010, 2013, 2016 and 2019, refer to Microsoft's website.

5. After you change the throttling policy, make sure to assign it to particular accounts.
6. Run the following cmdlet to assign the newly created policy (e.g. EdbMailsPolicy) to the admin account used for migration in EdbMails application:
   
   

   Set-Mailbox "<mailbox name>" -ThrottlingPolicy EdbMailsPolicy

   The parameter 'mailbox name' is the mailbox name or alias address.

   Use the following cmdlet to assign the throttling policy to all users in an organization:

   Set-ThrottlingPolicy "EdbMailsPolicy" -ThrottlingPolicyScope Organization

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