The completion of the Discovery Phase is an important milestone and provides the essential information necessary to help create a more detailed migration plan.  Here are some of the key considerations when planning a migration.

• Performing pilot/smaller scale migrations to validate migration configuration and understand performance to help identify any changes that may be required in the environment, including adding additional PMA servers.
• Understanding business priorities and data volumes to help determine the order of the migration.
• Initiate User Acceptance Testing (UAT) planning.

Delta Migration

If the source system is still active, then after an initial migration, customers may execute a ‘top up’ or otherwise known as a ‘delta migration’.  In this way, the bulk of the data is migrated, and the delta migration allows any subsequent updates that occurred on the source to also be migrated.  Note that in such cases, the target is overwritten so it’s important for users to understand this and only make and changes to documents in the source platform.  For more information on Delta Migrations see Delta Migrations.

 

8.1.1.  Content Type Planning

• Creating new Target Content Types

There may be source content types that have no current equivilent in the target and so decisions need to be made as to whether they should be mapped to an existing target content type or whether a new content type is created in the target.

Once these content types are created in the target then they can be mapped to using the Content Type Mapping feature.

• Mapping several source Content Types to single Target Content Type

In some migrations, customers may wish to simplify the existing content types and so map several different content types in a source to a single content type in the target.

• Separating single content type into many target content types

There can be scenarios were a single source content type needs to be separated out into more than one target content type.  PMA allows the creation of ‘Custom Content Type’ and allows the user to define criteria using the metadata of the item to identify them as a particular content type which can then be mapped to a suitable target content type.  See Custom Classification for more details.

• Sign off on metadata mapping

It’s essential that all source fields are understood for all content types so that metadata mapping is correctly configured and signed off to move the data to the target.

 

8.1.2.  Structure Mapping

Each of the existing source locations needs to be reviewed and as applicable, the target location for these needs to be determined as part of this planning process.   See

Phase 2 – Structure mapping for more details.

When designing target layout be aware of limitations in SharePoint that may create performance issues.  See  also:-

https://support.microsoft.com/en-us/topic/cf37b449-a2a7-4ef9-9f4d-aab826db5b30 - Understanding and managing large lists.

https://docs.microsoft.com/en-us/office365/servicedescriptions/sharepoint-online-service-description/sharepoint-online-limits for more information on SharePoint Online limits.

 

8.1.3.  Security

The security mapping will export lists of users, groups and permissions that may need to be mapped.  See Security Mapping for more details.

Decision on what User in the target system should items be associated with if the source user is not in the target system e.g. Leavers

It is strongly recommended to review/simplify permissions as part of the migration.  For example, putting permissions on the SharePoint Libraries and Folders rather than at an individual item level due to SharePoint limitations as SharePoint only allows 50,000 unique permissions in a single library.

 

8.1.4.  Shortcut Links/Embedded Links processing

Decision on whether to migrate shortcut links from source to target.  Note Shortcut Link migration occurs after all source items are migrated and is a much slower process.

Decision to convert links embedded within documents to resolve to new locations.  This will also significantly impact migration performance.  Note: Password protected/encrypted items cannot be processed.

 

Phase 2 – Structure mapping

Structure Mapping is used to define where the source folders/containers are migrated to in the target.  The location details in the Target Connection are combined with the information here to allow the full location to be determined. It is is one of the key elements within the Migration Preparation phase following on from successful Discovery and detailed planning.

It’s important to bring this information and an understanding of the target and requirements of the business and end users to create a set of rules, to ensure data is migrated to the correct target location.

 

 

There are three structure mapping options that may be available depending upon the exact target location specified. See Add a New Target Connection.

• Recreate using Source Hierarchy

This will create the source folders below the specified target location in the migration job.  This option is only available when the target location is a Document Library or Folder and the source location is also a folder.

• Restructure using Folders/Containers

This feature allows folders to be reorganized during the migration by ‘mapping’ source containers to target containers.  The assignment between source and target containers is done using a .CSV file which can be download and then imported after editing.

• Restructure using Item Metadata

Metadata structure mapping is a feature whereby the target location for items is based upon customer written rules that use source item metadata properties. The assignment between source item metadata and target folders is done using a .CSV file which can be download and then imported after editing.

Note: To update any structure mapping entries, it’s necessary to first delete the existing structure mapping before then importing new mappings.

Once any items have been processed in the Migration phase then it’s not possible to alter the structure mapping.  To alter the mapping, it’s necessary to use the Undo option which will first delete any migrated items and provides the option to undo the current structure mapping.