Microsoft 365 throttling

Throttling is a process that helps maintain server health and responsiveness by actively controlling excessive use of resources. It limits the number of concurrent requests to a service, preventing resource overuse and ensuring reliable performance.

How throttling functions

Exchange Online

Throttling in Exchange Online helps to ensure server reliability and uptime by limiting the amount of server resources that a single user or application can consume. Exchange Online resources, such as mailboxes and other related objects, are constantly monitored, and the Exchange Web Services (EWS) budgets assigned to each tenant or organization change accordingly.

When high-load factors are detected, EWS connections are proportionally restricted, and server performance degrades as a result. Even if a user is within their throttling limit, they may still experience slowdowns until the resource's health returns to operational levels.

SharePoint, OneDrive for Business, and Teams

Like Exchange Online, throttling is also used with SharePoint, OneDrive for Business, and Teams to maintain optimal performance and reliability of their respective services. With these three services, throttling uses Microsoft Graph APIs to limit the number of user actions and concurrent calls, preventing the overuse of shared resources. This guarantees a more stable and predictable performance when multiple tenants are using these services at the same time.

How to alleviate throttling

Throttling can slow down Microsoft 365 backup and restoration processes in ActiveProtect by limiting the number of concurrent requests. Any Microsoft 365 service may encounter throttling issues. Also, since backup and restoration speeds are sometimes influenced by the active Microsoft 365 throttling policy, adjusting configurations in our backup software may not fully resolve the issue.

If you experience throttling while backing up or restoring large amounts of data, you can temporarily turn off EWS throttling in Exchange Online.