Some organizations adopt a slow pace with system migrations, working out issues of coexistence. Other organizations migrate quickly, minimizing the coexistence time frame and disruption to the business. From a project-planning standpoint, it is necessary to perform migrations quickly and focus on ways to optimize a rapid deployment rather than spend too much time on coexistence issues. Although the base services of the Migration Wizard meet some user and administrative requirements, you'll need to implement specific configuration steps for others. This reduces the number of servers and keeps mail among users of an organizational or business unit on the same server, increasing delivery performance and reducing LAN traffic.
Exchange easily accommodates thousands of users on a single server with sub-second response time.
This approach requires additional disk space on the Exchange server, but reading data locally is more efficient than reading it over the network. Increase performance by specifying a temporary migration directory on a dedicated physical disk drive, allowing the wizard to write intermediate files on this disk subsystem and store the data on another. Mail databases copied to the Exchange server. Migrated mailboxes receive a separate copy of single-instance stored messages. This is due to limitations in the tools supplied by Lotus for full mailbox moves.