Nothing is permanent: Children grow, weeds sprout, and occasionally you need to move Microsoft Exchange Server mailboxes and systems. Therefore, knowledge about what you can move, where, and with what side effects is useful.
Moving Exchange Server 5.5 Mailboxes
Mailboxes are probably the most commonly moved objects in Exchange. How frequently you need to move mailboxes depends in part on how you allocate mailboxes to home servers. Most often, a user's physical location determines how you assign a mailbox to a server; when a user relocates, you might also need to relocate his or her mailbox.
Using Exchange Server 5.5's Move Mailbox tool is the simplest approach to moving Exchange Server 5.5 mailboxes. (You access Move Mailbox from Microsoft Exchange Administrator's Tools menu.) This tool will move Exchange Server 5.5 mailboxes to another Exchange Server 5.5 or Exchange 2000 Server system in the same site as the original mailbox location. You can't use this tool to move mailboxes between sites or organizations.
A nice feature of Exchange Server 5.5's Move Mailbox tool is that you don't need to involve users in mailbox moves. When a user connects to his or her old home server after a mailbox move, that server generates a Messaging API (MAPI) referral, and the MAPI client updates the user's profile to point to the mailbox's new home server.
The Move Mailbox tool also rewrites a mailbox's distinguished name (DNs) and the DN of each item in the mailbox. Every Exchange Server object has a DN that clearly points to only that object. When Move Mailbox relocates Exchange Server objects, their rewritten DNs must remain unique.
With Exchange Server 5.5's Move Mailbox tool, you can select as many mailboxes as you want and move them in one batch. However, Move Mailbox processes only one mailbox move at a time.
When you use Move Mailbox to move Exchange Server 5.5 mailboxes between servers, all mailbox data flows through remote procedure calls (RPCs) to the machine on which you're running Exchange Administrator's Move Mailbox tool. In other words, you'll be in for a long night if you use your home workstation to run Move Mailbox and a dial-up connection to relocate 1000 mailboxes. For best performance, log on to either the source or target server, then run Move Mailbox from that server. Also, plan large-scale moves for times when server usage is low: Moving a user's mailbox while he or she is logged on to the mailbox isn't a good idea.
Moving Exchange 2000 Mailboxes
Exchange Server 5.5 mailboxes are Exchange Server directory objects. In Exchange 2000, Active Directory (AD) user objects' attributes point to mailboxes, and you use the Microsoft Management Console (MMC) Active Directory Users and Computers snap-in to move Exchange 2000 mailboxes.
To relocate Exchange 2000 mailboxes, simply select the mailboxes you want to move, right-click them, and select Exchange Tasks, Move Mailbox. The resulting dialog box, which Figure 1, page 84, shows, lets you choose the selected mailboxes' destination server and mailbox store. Although Exchange Task Wizard's Move Mailbox function can't move mailboxes between Exchange Server organizations, it can easily move Exchange 2000 mailboxes between administrative groups.
Like Exchange Server 5.5's Move Mailbox, Exchange Task Wizard's Move Mailbox process is transparent to clients. However, Exchange Task Wizard's Move Mailbox doesn't
suffer from the bottlenecks that Exchange Server 5.5's Move Mailbox does. Exchange Task Wizard's Move Mailbox transmits mailbox data directly from the source server to the target server.
The Exmerge utility helps fill the gaps in Exchange 2000's and Exchange Server 5.5's built-in mailbox-moving functionality. You can use Exmerge to move Exchange Server 5.5 mailboxes between servers in different sites. You can also use Exmerge to move Exchange 2000 and Exchange Server 5.5 mailboxes between Exchange Server organizations. Although Exmerge can also be a key migration tool, the topic of migrating an Exchange Server 5.5 system to Exchange 2000 is too complicated and lengthy to pair with this discussion of mailbox and same-version server moves.
You can find the latest release of the multipurpose Exmerge utility in the Exchange 2000 CD-ROM's \support\utils\i386\exmerge folder. This version of the utility runs only on Windows 2000 machines but works with both Exchange 2000 and Exchange Server 5.5 mailboxes. This release sports several useful enhancements—not the least of which is the ability to process multiple mailbox moves simultaneously—that make chasing Exmerge down worth the effort. If you don't have an Exchange 2000 CD-ROM handy, you can probably sweet-talk a copy of Exmerge out of Microsoft Product Support Services (PSS).
To move a group of mailboxes between organizations, use Exmerge in batch mode, as Microsoft recommends. You can feed Exmerge a list of the DNs of the mailboxes you want to move, and the utility processes the moves simultaneously. However, before you run Exmerge, you need to create the mailboxes on the target server to ensure that target DNs exist. The utility exports each old mailbox's email to a personal store (PST), then reimports the email to the new mailbox you've created. You can perform such an export and import procedure manually, but the process would be tedious for one mailbox, let alone hundreds or thousands.
Exchange Server 5.5 and earlier provide recipient containers, which are containers that you can create to hold mailboxes and custom recipients. (AD's organizational units—OUs—are the rough equivalents of Exchange Server 5.5's recipient containers.) Administrators often create recipient containers to group users by location, department, or other seemingly convenient criteria (this practice isn't one I recommend; you can use other methods to achieve the same grouping effect). Recipient container objects take their container names as part of their DNs, which complicates moving these objects between containers. Only Exmerge can rewrite an individual recipient's DN and let you move this recipient to another container on a different server. However, Exmerge can't move recipients between containers on the same server.
Exmerge has a few additional limitations for mailbox moves. Exmerge doesn't guarantee that its moves will preserve any data other than messages, so don't expect all your rules to relocate. This rule-relocation problem arises because Exchange Server rules use folder IDs rather than folder names. When you move a mailbox, the folder IDs often change. Make sure you warn your users about this limitation before you move their mailboxes. Also, running Exmerge can take quite a bit of time, so if you need to move a lot of mailboxes from one server, consider moving the server instead of the mailboxes.
How easily you can move a server depends on the Exchange Server versions your systems run, the server's location (i.e., its group, site, or organization), the location to which you're moving the server, and your Exchange Server organization's design. Moving Exchange 2000 machines between administrative groups is probably the least complicated scenario—but only because you shouldn't make such a move at all. If you decide to disregard this advice and use Win2K's ADSI Edit tool to make a move manually, don't go crying to PSS if you break something: Microsoft officially doesn't support Exchange 2000 moves between administrative groups. To move Exchange 2000 systems between routing groups, simply use Exchange System Manager (ESM) and drag systems between the groups.
If you run only Exchange Server 5.5, you can use the Move Server Wizard (MSW) to move servers between organizations or sites within an organization. To move a server, the MSW needs to modify the DN of every object related to or homed on that server. Before you run MSW, make sure you've read and understood its documentation and release notes. I also recommend that you read Tony Redmond, "How to Rebuild Your Exchange Organization," January 1999.
MSW doesn't move Exchange 2000 systems between organizations. In fact, Exchange 2000's only use for MSW is to move Exchange 5.5 systems into a mixed-mode organization. Microsoft purportedly is developing better server-moving tools for Exchange 2000.
Moving On Up
The need to move mailboxes or Exchange Server systems is inevitable. After all, nothing is permanent: Even the procedures for moving Exchange Server objects change. However, inevitable changes won't always be annoyances. Although each new Exchange Server product version revises object-moving procedures, these changes can improve object-moving capabilities to let you easily move what once was immovable.