5. During Migration
We arranged that, on logging on to https://webmail.ox.ac.uk/ a message stated that a migration was in progress and when it started was also displayed. The migration process was not dependant on the size of the mailbox, but rather the number of messages in the mailbox. Each mailbox could be migrated at a rate of approximately 20,000 messages per hour, and 36 migrations could be run in parallel across the six migration servers in the migration cluster.