The default Agents Host Account (initially displayed on the Default Agent Host page of the Exchange server Properties) is set when you add source or target organization to migration project (see the Registering Source and Target Organizations section of the Migration Manager for Exchange User Guide for details).
If necessary, you can change the default Agent Host Account by clicking Modify on the General | Default Agent Host page of the corresponding server properties in the Migration Manager for Exchange Console.
To go on using the default Agent Host Account for Exchange migration, grant the permissions required for Exchange migration to this account.
The Agent Host Account should be a member of the local Administrators group on the license server (unless alternative credentials are used for the license server).
To add the Agents Host Account to the local Administrators group on the license server perform the following:
Perform the steps described in the related subtopics to ensure that your Exchange environment is ready for migration:
Before implementing Migration Manager in your production environment, back up your Exchange infrastructure. We recommend that Active Directory data be backed up at least twice a day during migration.
When Migration Manager for Exchange synchronizes mail and public folders, for every megabyte of data migrated from the source to the target, a transaction log file of equal size is generated on the target Exchange server. Exchange-aware backup applications purge the transaction logs after the backup completes. By the time the backup finishes, all logged transactions have already been applied to the store and backed up to tape, making log cleaning safe.
Large transaction logs that are generated during mailbox migration quickly occupy free disk space. To work around this problem, perform one of the following:
Note also that Microsoft recommends turning OFF circular logging on the Exchange server. For more information, refer to Microsoft Knowledge Base article 147524, “XDAM: How Circular Logging Affects the Use of Transaction Logs.”