Running Exchange Server 5.5 on Windows 2000

Introducing Win2K to your environment

Exchange 2000 Server has rich new features and excellent performance. However, migrating Exchange Server 5.5 to Exchange 2000 requires that you first successfully deploy a solid Windows 2000 Active Directory (AD) architecture in your organization and that AD replication works. Until you're ready to upgrade to Exchange 2000, you can reap the benefits of running Exchange Server 5.5 on the new OS. Let's look at what you can do.

Win2K's Benefits
Win2K offers several benefits to your organization. First, Win2K offers significant enhancements over its predecessor, especially in terms of performance. Benchmarks demonstrate that the Exchange Server 5.5 and Win2K combination dramatically increases the maximum number of users supported on one server. For example, a February 2000 test of Exchange Server 5.5 and Win2K Advanced Server on an 8-way Compaq ProLiant 8500 with 4GB of RAM and the Exchange database on a RAID 0 fibre channel array supported the equivalent of 33,400 concurrent users with a response time of 200 milliseconds (ms). You can obtain more information about this test in the Microsoft article "Compaq Achieves 33,400 MMB on the ProLiant 8500 550/2m System—Highest MMB on an Eight-Processor System".

This performance level means that you can reduce the number of Exchange servers in your organization. However, good practice is not to exceed 3000 or 4000 users on one server. Tony Redmond and Pierre Bijaoui's Windows 2000 Magazine article "Exchange 2000 Performance Planning" (April 2000) explains how to configure Exchange servers for maximum performance.

Second, introducing Win2K in your environment is the first step in migrating to Exchange 2000. The Active Directory Connector (ADC) requires the Win2K Exchange Server 5.5 configuration to synchronize the Exchange 5.5 Directory with Win2K AD. Furthermore, running Win2K is a good way to demonstrate Win2K features (e.g., performance, administrative enhancements, scalability) to people who are dubious about the new OS.

Third, Win2K's new backup and restore tools let you back up Exchange Server databases to disk drives and to tape. Using network or local drives as backup devices radically decreases the time you need for backups and restores, unless you're using a LAN-free backup solution with Storage Area Networks (SANs).

System Requirements
Win2K supports Exchange Server 5.5, Standard Edition (Exchange 5.5/S) and Exchange Server 5.5, Enterprise Edition (Exchange 5.5/E) with Service Pack 3 (SP3) running on a domain controller or member server. In addition to this basic system requirement, you must take into account a series of important considerations such as administering the new OS from Windows NT consoles, rewriting installation and configuration procedures, debugging and troubleshooting the configuration, and planning a migrating strategy. Each consideration is extensive and deserves discussion beyond the scope of this article. Here, I discuss practical installation procedures and running Exchange Server 5.5 on Win2K in the existing architecture.

Two Exchange Server 5.5 configurations don't work with Win2K. Win2K doesn't support the Transport Protocol, class 4 (TP4); therefore, if you use X.400 over TP4, you must change the Message Transfer Agent (MTA) stack to TCP if the link between Exchange and the other system supports this protocol.

Second, if you run X.400 over the X.25 protocol, you must check the Windows Hardware Compatibility List to ensure that Win2K still supports the X.25 card you're using. Win2K supports all the recent Eicon X.25 cards, and Exchange Server 5.5 supports Eicon cards without a special driver.

Finally, be sure that the backup software you use in an NT 4.0 environment works with Win2K. However, many backup software products use agents for Exchange Server, based on Exchange Server 5.5 APIs, so they're usually compatible with Win2K.

System Configuration
You can use two possible configurations: You can run Exchange Server 5.5 on a Win2K member server of an NT 4.0 domain or on a Win2K AD domain controller. For introducing Win2K into an NT environment, I suggest that you use the first option, for several reasons. First, AD replication consumes a great deal of system resources (e.g., memory, CPU, disk I/O, network bandwidth); therefore, using Exchange on AD might degrade system performance. Second, you must establish trusts between the NT 4.0 and Win2K domains; therefore, you must modify the existing environment. This modification requires careful design—a subject that belongs to a discussion of Win2K migration strategy. Finally, you must change the Lightweight Directory Access Protocol (LDAP) port number of the Exchange Directory Service (DS) because AD uses TCP port 389 for LDAP and for the old DS. Therefore, you must change the LDAP default setting on the client.

I assume that you already have a TCP/IP network on which you want to configure Win2K and Exchange Server 5.5. I also assume that you'll install the server and the OS from scratch to avoid interference with the existing NT domain and to simplify the installation. If you don't install the server from scratch, you must upgrade the server to a domain controller and later use dcpromo.exe (i.e., the server promotion wizard) to demote it.

Standalone System Installation
To configure the system, you must install the Win2K member server, install Exchange Server 5.5, and install the required connectors. Here are the installation steps for a standalone system.

Cluster Installation
Installing a cluster in a Win2K environment is similar to installing a cluster in an NT 4.0 environment. Refer to Dennis Lundtoft Thomsen, "Tips for Clustering Exchange Successfully," April 2000, for a detailed description. Here are the main differences from the standalone installation procedure.

For a 4-way cluster, install Win2K AS or Win2K Datacenter Server. On both nodes, complete all the steps for a standalone server through Step 4. Now, install Microsoft Cluster Services (MSCS) on the first node by double-clicking the Control Panel Add/Remove Windows Component applet and selecting Cluster Service. After the first node is running MSCS, install the Cluster Node on the second node. For more information about installing a cluster, consult the Win2K Help on the Win2K Server CD-ROM.

When the Win2K cluster is running, install the Exchange cluster as you do in NT 4.0. For more information, see cluster.doc on the Exchange Server 5.5 CD-ROM. (Note that Microsoft doesn't support OWA in this environment.) Next, install SP3 on the primary node and then on the secondary node.

Install the IMS connector. MSCS doesn't support other connectors. For other software, follow the products' installation guide.

A Winning System
Today, you don't need to run Exchange Server 5.5 in the NT environment, especially when you're building a new system. Take advantage of running 32-bit applications on Win2K. If you move to Win2K now, you'll prepare your environment for more extensive use of Win2K and for Exchange 2000.