EDIT: This post was updated on 4/29/2008 to add more detail about the Exchange-aware backup on next version of SBS.

In a previous blog post, we wrote about the various versions of Exchange Server and their support for Windows Server 2008. Now that Windows Server 2008 has released to manufacturing, we wanted to briefly discuss some specific issues that you might encounter as you deploy Windows Server 2008 in your environment, particularly if you're planning on running Exchange Server 2007 Service Pack 1 (SP1) on Windows Server 2008.

Exchange 2007 SP1 is the only version of Exchange Server that is supported for installation on Windows Server 2008. Now that Windows Server 2008 has RTM'd, Exchange 2007 SP1 is fully supported on Windows Server 2008 in production environments. No other version of Exchange Server, including the released to manufacturing version of Exchange 2007, is supported on Windows Server 2008.

As stated in the blog, Mission Impossible: In-Place Upgrading Microsoft Exchange Server 2007 from Windows Server 2003 to Windows Server 2008, you cannot upgrade the operating system in-place while Exchange 2007 (RTM or SP1) is installed. Thus, the only way to run Exchange 2007 on Windows 2008 is to do a fresh install of Windows 2008 and then install Exchange 2007 SP1.

Windows Server 2008 Improvements that Benefit Exchange

Windows Server 2008 includes a number of improvements and enhancements that can directly benefit servers running Exchange 2007 SP1. There are many benefits to running Exchange 2007 SP1 on Windows Server 2008. Just to name a few:

  • Support for multi-subnet failover clusters When running in a Windows Server 2008 failover cluster, Exchange 2007 SP1 includes support for geographically dispersed clusters for failover across two subnets. This support includes both Cluster Continuous Replication (CCR) environments and Single Copy Clusters (SCC).
  • Faster log file shipping Cluster Continuous Replication and Standby Continuous Replication are two forms of log shipping that use the Server Message Block (SMB) protocol to copy log files from a source storage group to a passive or target storage group. Windows Server 2008 includes SMB version 2, which provides a significant increase (around 30-40%) in SMB-based file copying throughput and performance.
  • Reduced downtime for hardware maintenance Windows Server 2008 enables a variety of core hardware components to be added, removed or replaced without requiring system downtime. These processes are often referred to as "hot add", "hot remove", "hot replace" because the system remains active and continues providing service and data access while the hardware maintenance is occurring. Dynamic hardware partitioning in Windows Server 2008 includes support for hot add and replacement of processors and memory, as well as hot pluggable PCI Express cards. Of course, support for this is available only with the appropriate hardware. If you're not sure if your hardware is capable of running Windows Server 2008, you can download the Microsoft Assessment and Planning tool to securely inventory your existing servers and generate a migration report for Windows Server 2008.
  • Near-zero downtime when fixing NTFS corruption In Windows Server 2003 and earlier, fixing NTFS corruption required taking the server offline to run the Chkdsk utility. The downtime associated with this process can be significant, particularly when the volume being checked is quite large. Windows Server 2008 includes a feature called self-healing NTFS, which attempts to correct corruptions of an NTFS file system while the system is online, and without requiring Chkdsk to be run. With self-healing NTFS, the file system is always available, NTFS corrects all detected problems while the system is running, and Chkdsk does not have to run in its exclusive mode except in extreme conditions.
  • Greater scalability for Client Access servers that provide Outlook Anywhere services Windows Server 2008 includes a Next Generation TCP/IP stack that removes the RPC Proxy Service TCP connection limits imposed by Windows Server 2003 and earlier versions of Windows. Specifically, the RPC Proxy Service, the Windows component that enables RPC over HTTP, now supports per-IP address connection-limits. Whereas the RPC Proxy Service in Windows Server 2003 supports a maximum of 65,535 connections, regardless of the number of IP addresses assigned to the server, the RPC Proxy Service in Windows Server 2008 supports a maximum of 65,535 connections per IP address.
  • Easier deployment Windows Server 2008 includes Exchange 2007 installation dependencies, such as Microsoft Management Console (MMC) 3.0, Windows PowerShell, and .NET Framework 2.0. As a result, you don't need to separately download these prerequisites in order to deploy Exchange 2007 SP1 on Windows Server 2008. Instead, you can quickly install them from the new Server Manager MMC console in Windows Server 2008, or install them from the command-line version of Server Manager.
  • Support for IPv6 Windows Server 2008 includes support for IPv6, and Exchange 2007 SP1 supports IPv6 on Windows Server 2008 when used in tandem with IPv4. For more information, see IPv6 Support in Exchange 2007 SP1.

For more information about the many other changes in Windows Server 2008, including several other changes which can benefit Exchange environments, see Changes in Functionality from Windows Server 2003 with SP1 to Windows Server 2008.

Windows Server 2008 is an excellent platform for Exchange 2007 SP1, but if you're using, or planning to use, Windows Server 2008 as the operating system for your servers running Exchange 2007 SP1, please be aware of the following issues.

In-Place Upgrade of Operating System

As previously mentioned, you cannot perform an in-place upgrade from Windows 2003 to Windows 2008 when Exchange 2007 RTM or Exchange 2007 SP1 is installed. You must first uninstall Exchange, Windows PowerShell and other components (assuming the system is a standalone server and not clustered), and then upgrade the operating system, or you must perform a migration by using the Move-Mailbox functions or database portability to migrate from your existing server to a new server.

Exchange-Aware Backups on Windows Server 2008

Unlike previous versions of Windows, Windows Server 2008 does not include a backup utility that supports the Exchange ESE streaming backup APIs. The Windows 2008 backup application, Windows Server Backup, cannot be used to take backups of Exchange. NOTE: For customers running the upcoming version of Windows Small Business Server 2008, Windows Server Backup will be able to take Exchange-aware backups.

Exchange still includes the ESE streaming backup APIs, but the absence of an Exchange-aware backup application in Windows may come as a surprise to many. Another change we made that may also affect you is the removal of remote streaming backup support on Windows 2008.

This leaves you with two choices for taking Exchange-aware online backups when running Exchange 2007 SP1 on Windows 2008:

  1. Move to a Volume Shadow Copy Service (VSS)-based backup application. You can use Microsoft System Center Data Protection Manager (DPM) 2007 or a third-party backup application that supports Exchange-aware VSS-based backups of Exchange 2007 SP1 on Windows Server 2008. Windows Server Backup in Windows 2008 is a VSS-based backup application, but there are additional requirements for Exchange backups and restores beyond using the VSS Framework; for example, checking the database and log files for corruption during backups is not part of the VSS Framework and it is not performed by Windows Server Backup.
  2. Use a Third-Party application that supports ESE streaming backups using a local backup agent on the Exchange server. Because the ESE streaming APIs remain in Exchange 2007, you can still use them to backup Exchange. But to do that, you must use a third-party backup application that runs a local agent on the Exchange server so that the streaming backup is made locally, and not remotely. You cannot take remote streaming backups of Exchange 2007 SP1 on Windows 2008 with or without a third-party product. Any streaming backups that are performed must be performed locally on the Exchange server. An ESE streaming backup application that uses an "agent" locally on the Exchange server to remotely backup Exchange is considered a local streaming backup and not a remote streaming backup because the application's agent component is running locally on the Exchange server.

Read-Only Active Directory Servers

Windows Server 2008 introduces the concept of read-only domain controllers (RODCs) and read-only global catalog servers (ROGCs). RODCs and ROGCs provide a way to deploy an Active Directory directory server more securely in locations that require fast and reliable authentication services but cannot ensure physical security for a writable domain controller. For more information about RODCs, see AD DS: Read-Only Domain Controllers.

No version of Microsoft Exchange uses read-only domain controllers or read-only global catalog servers because all versions of Exchange require the ability to write configuration information to Active Directory. Microsoft Exchange works in environments that include read-only domain controllers or read-only global catalog servers, as long as there are writeable domain controllers available. Exchange 2007 effectively ignores read-only domain controllers and read-only global catalog servers, and Exchange 2007 requires a writable directory server in the Active Directory Site containing Exchange 2007 servers or users.

Cross-Operating System Feature Support

Some Exchange 2007 SP1 features require the same operating system in order to use them. For example, Standby Continuous Replication (SCR), a new type of log shipping in SP1 that can replicate data from a source to multiple targets, requires that the source and all targets run the same operating system. This means that you cannot have a source running Windows Server 2003 that replicates to a target running Windows Server 2008.

Another example is management of cluster continuous replication environments and single copy clusters. Windows Server 2008 represents a clean break from the Cluster APIs included in earlier versions of Windows Server. Because the Cluster service does not allow you to use the cluster management tools for remote administration of failover clusters across different operating systems, you cannot use the Exchange management tools for remote administration of failover clusters across different operating systems.

Meeting the Prerequisites

Once you're ready to deploy Exchange 2007 SP1 on Windows Server 2008, you'll want to first make sure you've met all of the necessary pre-requisites. One important pre-requisite to keep in mind is the installation option for Windows Server 2008. I am referring to the "Server Core" installation option and the "Full" installation option for Windows Server 2008.

Windows Installation Options and Exchange Server 2007 SP1

The Server Core installation option is a new for Windows Server 2008. A Server Core installation provides a minimal environment for running specific server roles that reduces the maintenance and management requirements and the attack surface for those server roles. To provide this minimal environment, a Server Core installation installs only the subset of the binaries that are required by the supported server roles.

As you probably already know, Exchange 2007 is the first application that leverages and integrates with the Windows PowerShell. As you may also already know, much of Exchange 2007 is written in managed code that uses the .NET Framework. Neither Windows PowerShell, nor the .NET Framework can be installed on the Server Core version of Windows Server 2008. As a result, the Server Core version of Windows Server 2008 cannot be used to host Exchange 2007 SP1. Instead, you must use the Full Version installation option.

After you've installed Windows Server 2008, you must install other prerequisites before you can install Exchange 2007 SP1. Instructions for installing these prerequisites can be found here.

Known Incompatibilities

One known Exchange-related incompatibility with Windows Server 2008 is the downloadable Messaging API Client and Collaboration Data Objects 1.2.1 package. Currently this tools package operates on Windows Server 2003 or Windows XP. We're working on validating these tools against Windows Server 2008 and expect to have an updated version released.

Migrating to Windows Server 2008

Our official guidance and procedures for migrating Exchange 2007 from the Windows Server 2003 operating system to the Windows Server 2008 operating system can be found in this month's Exchange Server TechCenter Feature Article, Migrating Exchange 2007 on Windows Server 2003 to Exchange 2007 SP1 on Windows Server 2008.

For More Information

- Scott Schnoll

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