Office 365 Email Limits: How and When to Disable EWS Throttling in MS 365 & Exchange Online?

You cannot manually disable the EWS throttling in Office 365 (Microsoft 365). You have to open a support request through the Admin Center for disabling these services in the tenant. In this article, we will be discussing the stepwise process to disable the EWS throttling in Microsoft 365 (Exchange Online).

What is EWS Throttling?

The Exchange Web Services (EWS) is a part of Exchange Server or Office 365 where policies are in place to regulate the concurrent operations, requests, and other resources that a user or application can use. Migration, especially with very large mailboxes, can cause degradation of services. For this reason, the EWS protects the service, thus maintaining the service reliability and uptime. Such protections include:

• Concurrency limits, which control and limit simultaneous calls.
• Burst limits, which control the number of requests that can be made in a short time.

The Exchange Web Services (EWS) will not kick in in a normal day-to-day usage. It is a rare case when it would jump in. The service will push its policies during data migrations, archive ingestion, large batch exports/imports, and other bulk operations which would normally exceed the limits.

How will EWS Impact the Operations?

During a migration, there is a lot of data movement. When the policies hit, there are some repercussions that you should know about.

• Slow throughput of data for the migration which result in longer migration effort.
• Frequent retries slow down the migration and access of the data.
• This will affect the operations and deadlines of the project.
• High CPU and memory usage on the servers.
• Slow network throughput.

When to Disable the EWS Throttling?

The Exchange Web Services (EWS) should only be disabled during very large migration or ingestion operations. Here are some ideal scenarios where you can disable the throttling:

• Large migrations including thousands of mailboxes.
• Hybrid Exchange Server migrations.
• Cross-tenant migrations for local servers.
• Third-party software for archive data ingestion.

For Office 365, Microsoft operates on a shared-resource model where it creates a fair use of its connectivity. If these services are disabled permanently, it would degrade the service for the other tenant and increase the chance of misuse of service. With such limits, it does protect the stability of its services. This is the reason why Microsoft allows temporary relaxation of throttling mechanism and allows this for specific migration needs. The same reasons apply for on-premises servers and infrastructures.

How to Disable the EWS Throttling in Office 365?

The only option to disable the throttling in Office 365 (Microsoft 365) is by opening a support request through the Microsoft Admin Center. There is no way to manually disable the policies from the tenant using the global administrator. You can follow the below steps:

• Log into the Microsoft 365 Admin Center with Global Administrator.
• Click on Show all button in the left pane.
• Expand Support.
• Click on Help & Support.
• In the Support Assistant, enter EWS Throttling. This will ask you to run the test.
• After the test is complete, click on Contact Support.
• Follow the prompts to open the support ticket to have the throttling policies relaxed during your migration path.

How to Disable the EWS Throttling in Exchange Server?

When having large data migration or archive/data ingestion on an Exchange Server, you can disable the throttling services. First, you need to know the policies which are assigned to the service account or migration batch. For this, you can run the below command:

This command will show the policies which are currently applied.

You can use the below command to view the policy:

It is recommended to first create a new policy to disable the throttling policies.

Here’s the command:

Next, you need to disable or increase the EWS limit. Use this command:

You can set to unlimited so that there are no limits on the data import, migration, or ingestion.

When migrating a large amount of data, the above parameters are more relevant. You now need to assign the throttling policy to the service account by using the command below:

After this command is complete, you should run the following command:

Again run the Get-ThrottlingPolicy | FL command to confirm that the policy has been applied.

After the migration, you should re-assign the original policies to ensure the Exchange Server is protected.

How to Overcome the Migration Challenges?

The reason you would be throttled is by ingesting a lot of data at once and using an adaptive request will avoid the overwhelming of the services. Parallel mailbox processing will reduce the migration time. Incremental (Delta) synchronization is essential to ensure that only the changes are being migrated.

You can use specialized Exchange migration tool, such as Stellar Migrator for Exchange, to overcome the migration challenges. With this tool, you will have fast, reliable, and seamless migration, with minimal failures and predictable throughput. It also offers full real-time and post-migration reporting. It supports migration of user mailboxes, user archives, shared mailboxes, and public folders.

The tool can be used for the following migrations:

• Exchange Server to Exchange Server.
• Exchange Server to Office 365.
• Office 365 to Exchange Server.
• Office 365 to Office 365.

Conclusion

EWS Throttling is an essential part of Office 365 and Exchange Server to protect the throughput of the system and ensuring performance. Disabling it during migrations or permanently (on local server) can cause degradation of the services. However, this alone cannot guarantee a smooth and seamless migration of data. So, you should opt for specialized Exchange migration tool, such as Stellar Migrator for Exchange, for migration of data. This will ensure the time of relaxation of polices is short and data integrity is assured.