A few weeks ago, Microsoft published a guide on migration performance with Microsoft Exchange Online using various tools. We want to clarify where MigrationWiz fits in respect to throttling mechanisms and performance factors mentioned in this guide.
Many third-party migration tools use MAPI (Messaging Application Programming Interface) with an average throughput of at most a few hundred MBs per hour per mailbox. By comparison, MigrationWiz uses EWS (Exchange Web Service) which typically results in significantly higher throughput.
Unlike some native Office 365 migration tools, MigrationWiz can migrate as many mailboxes concurrently as you want. Leveraging our expertise in Microsoft Exchange, we’ve developed a migration solution that scales to hundreds of thousands of concurrent migrations.
The guide lists three throttling mechanisms that affect migration performance, two of which are related to using the EWS protocol. The EWS protocol is affected by (1) migration-service throttling and (2) resource health-based throttling. The third throttling mechanism, (3) user throttling, is the most restrictive but does not apply to the EWS protocol. It only applies to third-party migration tools listed on page 8-9. The two throttling mechanism that apply to the EWS protocol and MigrationWiz also affect all native Office 365 migration tools.
The guide also describes factors that apply to all migration tools for Office 365.
1) Source System
Many source messaging systems have throttling policies and inherent system capabilities that limit throughput. There is often no easy way to alleviate this type of issue. At best, users can follow procedures to optimize data source performance such as timing the migration when source servers are being used the least. MigrationWiz automatically selects migration servers that provides the fastest access to the data source and uses advanced techniques such as batching or buffering to optimize data transfers.
2) Local Resources
Many third-party migration solutions require deployment of on-premise software to perform Office 365 migrations. These servers require deployment of dedicated software and hardware in order to push data to Office 365. Limited local resources can result in performance bottlenecks.This, however, does not apply to MigrationWiz. MigrationWiz is a cloud-based migration solution that does not require any on-premise server deployment and provides “elastic” computing power to eliminate this bottleneck.
3) Access Method
For third-party migration solutions, the most common protocols used are EWS and RPC over HTTP. As per Microsoft’s white paper, ”Exchange Web Service (EWS) is the recommended protocol to use for migrating to Office 365 because it supports large data batches and has better service-oriented throttling.”. This matches precisely the access method MigrationWiz uses to migrate data to Office 365.
4) Office 365 Throttling
As explained above, Office 365 uses different throttling techniques to control the amount of inbound data. Resource health-based throttling affect all migration methods, though it does not affect migrations as much as other throttling mechanisms. MigrationWiz is only subject to a subset of these throttling techniques.
In conclusion, MigrationWiz is subject to most of the same throttling limits as those imposed on other migration solutions. However, MigrationWiz uses the recommended access method (EWS, not RPC over HTTP), and also eliminates all bottlenecks caused by having to deploy local migration resources.