The is almost always performed using specialized tools. Whether you use Microsoft’s SharePoint Migration Tool or some other tool by third-parties, the migration approach is more or less the same. This is because all tools require the SharePoint API and most leverage Azure for migrating larger volumes of data. Here are the basic steps involved in SharePoint tenant to tenant migration.
Preparing Source Environment
As a part of preparing the source environment for migration, the content has to be evaluated, analyzed, and triaged. Use this opportunity to identify the quantity and types of data that have to be migrated from the source environment. Determine the versions of the files that have to be made available on the new SharePoint Online tenant. Additionally, at this stage, it should be possible to estimate the size of the packages based on the number of files to be transferred and their sizes. It must be noted that in most cases, files move faster than list items and other objects. Additionally, the smaller the file size, the greater is the overhead. This knowledge would help in optimizing the project size.
Preparing Destination Environment
This step involves creating an account with SharePoint Online administrator or Site Collection administrator rights. If the new tenant has to be built from the ground-up, the admin will have to create site libraries and schemas. They will also have to replicate the structure of the document library along with any customizations before initiating the migration.
Initiating the Migration
Regardless of the tool that is used, the migration is initiated by creating endpoints. This involves providing authentication to the tool for the source and destination environments. The type of authentication such as NTLM, Kerberos, Multi-Factor Authentication, app-based authentication, and so on, not play an important role in determining the security of the process, but also the performance due to factors such as throttling by Microsoft.
Performing The Migration
At this stage, it is time to move contents from the source SharePoint Online tenant to the destination. The steps involved at this stage may vary based on the number of users and the tool. If there are only a few users, it is recommended to move all the contents in a single pass. If there are more users, some of the supported items can be moved first before a specific date, and subsequently, the remaining content can be transferred in delta passes.
Post Migration Steps
After the migration is complete, the tools typically generate reports detailing the items that have migrated, errors, and other data. Verify that