Migrating to Exchange 2000: A Personal Saga

I hope you're having a pleasant holiday season. This time of year, most organizations are in the middle of their year-end freeze and can't make any changes to their environment until after the first of the year. I, on the other hand, have been busy violating those rules and have started the Exchange 2000 migration of my Exchange 5.5 site. If you remember from my earlier columns this year, I have an Exchange 5.5 site consisting of a clustered Exchange server that I have to move to Exchange 2000—somehow. In this month's Exchange & Outlook UPDATE Special Edition, I share with you my progress and pains thus far.

Microsoft hasn't given Exchange 5.5 cluster owners much of a migration path to Exchange 2000. Our choices are limited: mailbox relocation or the "forklift" approach. In my case, I chose the mailbox relocation strategy—with a twist. I'll move all my mailboxes on the existing Exchange 5.5 cluster to an Exchange 2000 cluster, but I've planned an intermediate step. I need to move the mailboxes to another Exchange 2000 server before moving them to the Exchange 2000 cluster. I have a couple of concerns that have dictated this choice. First, my Exchange 5.5 cluster is the first and only server in my site. Therefore, that server is key for site configuration data as well as being the bridgehead server. As a result, we chose to do a bit of site redesign while moving to Exchange 2000 and, hopefully, cause minimal downtime for users. I also didn't have a lot of extra hardware lying around to accomplish everything—I had to use existing hardware while keeping the site and cluster up and running.

The plan we devised consists of the following steps. First, we create a new Exchange 2000 server in my Exchange 5.5 site. This server becomes the new bridgehead server and gets the Exchange 2000 Site Replication Service (SRS). We move the X.400 connector from the Exchange 5.5 cluster to this bridgehead server. Next, we turn the second node of the cluster (call it EX2) into a temporary Exchange 2000 mailbox server that houses the mailboxes while we rebuild the cluster to Windows 2000 and Exchange 2000. The third step is to move the mailboxes from the Exchange 5.5 cluster to the EX2 mailbox server. After we move all mailboxes to EX2, we rebuild the cluster (one node) to be an Exchange 2000 cluster with a virtual server named the same as the old Exchange 5.5 virtual server. Next, we move mailboxes to the Exchange 2000 cluster (again, running one node) from the EX2 server. Finally, we decommission the temporary server and rebuild it as the second node in the Win2K/Exchange 2000 cluster. The end result is a site with a bridgehead server acting as routing master, hub, and SRS for the site and servicing the cluster where the mailboxes are.

Thus far, we've certainly had our share of problems. As with all new software versions, we're learning about a few bugs in Exchange 2000 that didn't quite get fixed before Microsoft shipped it. We've also discovered how the weaknesses in our own infrastructure can severely affect Exchange 2000 (remember how important it is to get DNS and Active Directory (AD) right for Exchange to work well). In addition, I think the users in our site will attest to the fact that I have really delivered on the minimal downtime I promised. Overall, my plan and approach might seem a bit cumbersome and complicated—other methods can accomplish the task. However, based on the constraints we had, I think the plan is working out well as an example of making the best of the resources you have. The process is not over, however. In truth, we're still trying to stabilize the site after adding SRS and dealing with the problems with this service. But the outlook is hopeful.

We've learned several lessons thus far. First, you can never plan too much for your migration. Next, don't forget to test things before putting them into production. One unexpected lesson or bright spot is the single-seat administration capabilities of Win2K Server Terminal Services. Not having used Terminal Services for Exchange 5.5 and Windows NT 4.0, I'm impressed. As you think about starting your migrations after the year-end freezes are over, don't forget to understand, plan, and test.

Finally, I want to take this opportunity to thank you for your readership and recognize our sponsors for their support. Since our beginning in March 1998, Exchange & Outlook UPDATE has grown to be the third-largest email newsletter that Windows 2000 Magazine delivers. Thanks for putting us in the top heap. May your holidays be blessed and your new year filled with success.