What are the common migration strategies?

Big Bang Migration:

A single pass migration strategy that will move the entire mailbox in one pass after MX records are cutover.
A typical scenario consists in cutting over on a Friday evening and migrating during the weekend.

Pros:

• Cost-effective.
• Simplest to implement.

Cons:

• Migration may potentially not complete in time for various reasons.
  • Users accessing the new system may not have access to all their data when work resumes.
  • Any items created during or after the migration may be missed by a single pass.
  • Downtime may occur for some users if migration fails or takes too long.

Pre-Stage Migration:

A multi-pass migration consists of pre-staging a majority of the data prior to cutover and doing a Full (Delta) Pass after cutover.

Pros:

• Majority of data is available at time of cutover.
• Mitigate migration risks in which the majority of data will be available regardless of availability of source server at time of cutover.

Cons:

• Will not propagate updates, deletes, or moves of the items previously migrated in the first migration pass.

How do I configure a multi-pass migration?

Quick-Switch Migration

A quick-switch migration consists of pre-staging only the newest emails. New emails are accessible immediately at time of cutover by users and the remaining data is backfilled over time.

Pros:

• Initial migration is quick.
• Time between cutover and data availability is short.

Cons:

• Not all data is available at time of cutover for end users.

How do I configure a Quick-Switch Migration?​​​