By Michael Cherry [bio]
Posted: Apr. 7, 2008

• Sidebar: Server Core Application Compatibility

The following is the full text of an article published by Directions on Microsoft, an independent research firm focused exclusively on Microsoft strategy & technology. More samples of our content, as well as a list of upcoming articles and reports are also available.

As with all major OS updates, new and updated Windows Server 2008 features mean server applications need to be tested for compatibility with the new OS. Some Microsoft server applications will require a specific version or service pack that might not be available. Consequently, organizations may want to stage deployment of Windows Server 2008 by concentrating first on infrastructure services, in particular with the new Server Core installation, and other server roles that are less likely to be affected by application compatibility.

Applications that will require compatibility testing can typically be divided into three groups:

• Microsoft server applications (by version and service pack level)
• Third-party applications (such as non-Microsoft database engines, utilities, and security tools)
• In-house or custom line-of-business applications.

Although an organization likely can leave it to Microsoft and other software vendors to test their own applications, customers will want to verify the status of their vendors' applications and make plans to deploy compatible versions on Windows Server 2008. In addition, customers will want to use the application compatibility and logo testing tools provided by Microsoft to determine whether custom applications will run on Windows Server 2008.

Microsoft Server Application Status

In some cases, Microsoft applications still in Mainstream support are not supported on Windows Server 2008, and not all versions or service pack levels of other applications are supported. More often than not, only one specific version at a specific service pack level is supported.

A Microsoft Knowledge Base article divides server applications into three levels of compatibility: currently compatible, compatible in the future, and incompatible. Compatible means the application will install and run on Windows Server 2008, and Microsoft will support customers using that version. However, the fact that an application is compatible does not mean that the server and the application can be upgraded in place, or that it will run on every configuration of Windows Server 2008 (such as Server Core).

Currently Compatible

Approximately 15 Microsoft server applications, including Exchange Server 2007 SP1, SQL Server 2005 SP2, Windows SharePoint Services 3.0 SP1, and SharePoint Server 2007 SP1, are currently compatible with Windows Server 2008.

Microsoft recommends that before installing Windows Server 2008 on an existing server, users uninstall all applications that did not ship with Windows Server 2008 or that were not delivered via Windows Update. After the new server OS is installed and configured, compatible applications and any corresponding data can be reinstalled. For example, although Exchange 2007 SP1 is compatible with Windows Server 2008, it is impossible to do an in-place upgrade from Windows Server 2003 to Windows Server 2008 if the Windows Server 2003 computer is already running Exchange 2007 SP1.

Furthermore, customers should also keep in mind that Windows Server 2008's Server Core installation mode is not intended as an application platform, and therefore cannot support most server applications. Management, utility, and security software may need updating to run on Server Core. (For details, see the sidebar "Server Core Application Compatibility".)

Compatible in the Future

The Knowledge Base article lists approximately 22 Microsoft server applications, including Virtual Server 2005 R2 SP1, System Center Operations Manager SP1, and Windows Server Update Services 3.0 SP1, that will be compatible with Windows Server 2008 at some unspecified time in the future.

Virtual machines might be used to mitigate application compatibility by permitting customers to run incompatible server applications in a virtual machine on a supported guest OS. However, Windows Server 2008's native virtualization technology, Hyper-V, will not be released until mid-2008, and other popular virtualization software, such as VMware and Citrix's Xen, does not yet run on Windows Server 2008.

In addition, even when some applications are supported in the future, the level of support may be limited. For example, Microsoft Operations Manager 2005 SP1 agents will be able to monitor a server running Windows Server 2008, but the application itself, including its console and database, will not run on Windows Server 2008.

Incompatible

Approximately 11 Microsoft server applications, including Microsoft SQL Server 2000 (and earlier), Speech Server 2004 R2, Microsoft Internet Security and Acceleration Server 2006 (and earlier), Reporting Manager 2006, and the recently released Communications Server 2007, are incompatible with Windows Server 2008.

Although some of these applications are old or legacy versions, Communications Server 2007 is the current release and is in the Mainstream support phase of the product's life cycle. It will likely be compatible at some point in the future, although it may require a service pack.

Missing Information

The Windows Server 2008 Application Compatibility list is not complete. For example, the status of BizTalk Server 2006 and 2006 R2 is not listed (although a new version of BizTalk will likely be available in the first half of 2009). Other servers, such as Visual Studio Team Foundation Server and Mobile Device Manager, are not listed in any compatibility category, although Visual Studio 2008 Team Foundation Server's systems requirements document lists Windows Server 2008 as a supported platform.

Customers will have to monitor the Knowledge Base article or the product Web sites for more information about specific application compatibility.

Evaluating Custom Applications

The Windows Vista and Windows Server 2008 Application Compatibility Cookbook lists approximately 40 changes to Windows Server 2008 that could cause application compatibility problems. Each entry includes a brief description of the change, how the change creates application problems, how to mitigate the problem (if possible), and how to remedy it. Examples of changes included in the cookbook are new features such as User Account Control, Read Only Domain Controllers, and changes to existing features, such as Internet Information Services (IIS) 7.0.

User Account Control: Standard User Changes

Microsoft introduced User Account Control (UAC), a common feature of high-end OSs, in Windows Vista, and brought it to servers with Windows Server 2008. UAC is designed to encourage users to run the majority of applications that they need with a standard user account, which gives them access to only a limited set of permissions and privileges. By default, Windows Vista and Windows Server 2008 will run every application in standard-user mode, even if the user logs on as a member of the administrators group. Conversely, when users attempt to launch an application that has been marked as requiring administrator permissions so that it can modify system and global settings and behavior, the system will explicitly ask them to confirm their intentions to do so.

UAC has a high degree of impact on application compatibility because many applications expect that the user is by default an administrator, and these applications may fail when they try to update the Registry or protected areas of the file system while running in standard-user mode.

Customers can test for UAC-related problems by using the Standard User Analyzer or Standard User Analyzer Wizard, which are included in version 5.0 of the Application Compatibility Toolkit. (Note: In the current documentation, this tool is still called by its former name, the UAC Predictor Tool.) It may be necessary to rewrite applications to resolve problems with UAC. Special care should be taken to separate tasks that anyone can perform from tasks that require administrative privilege.

Read-Only Domain Controllers

A Read-Only Domain Controller (RODC) is a new type of Windows Server 2008 domain controller designed for organizations that need to deploy a domain controller in locations where physical security cannot be guaranteed, such as branch offices, or where there is no administrator to manage it. An RODC is a read-only replica of the Active Directory Domain Services database for a given domain. Because the feature is new and few applications store data in a domain controller, the impact on applications is moderate.

Applications that write to the Active Directory need to be rewritten to check that the target is a writable domain controller.

IIS 7.0

IIS 7.0 introduces granular control over the various IIS components, provides better security, and simplifies development. IIS no longer uses the Metabase, the data store used in previous versions of IIS, and now uses a flat XML configuration data store. For compatibility purposes, IIS 7.0 includes a compatibility layer for Metabase dependent scripts and applications.

In addition, several features have been retired and are no longer part of IIS 7.0, including the following:

IIS 5.0 Isolation Mode, which allows applications written for IIS 5.0 to run on IIS 6.0.

WebDAV, which extends the HyperText Transfer Protocol (HTTP) so that users can collaboratively edit and manage files on Web servers, has been removed from Windows Server 2008. Its replacement, a newly built WebDAV implementation, can be freely downloaded separately. This version of WebDAV will be fully supported during the Windows Server 2008 life cycle.

FrontPage Server Extensions, which support administering and authoring FrontPage Web sites, have been phased out of Microsoft developer tools as well as removed from Windows Server 2008, although they are available for separate, free downloading.

Sites relying on missing or retired components may fail, unless optional components are installed or IIS 7.0 WebDAV and FrontPage Extensions are downloaded. In the case of the deprecated Metabase, Microsoft has provided some migration APIs, but customers should consider that these methods will likely be retired in future versions of the product, and therefore it may make more sense to abandon them now rather than migrate applications that depend on them.

Why Some Server Applications Are Not Ready

Microsoft's most critical server applications, namely, the current versions of Exchange, SharePoint, and SQL Server, were updated for Windows Server 2008 before the general availability of the new OS. However, other product groups at the company, such as BizTalk Server, are waiting to make an update for Visual Studio, SQL Server, and Windows Server at the same time.

In general, Microsoft product groups focus on making the latest shipping version of their products work on the latest version of Windows Server 2008. Therefore, few product groups are willing to devote resources to making an older version of their products compatible with the new Windows Server, even if those products are still in Mainstream support. This shows, once again, that organizations should take the "Mainstream support" designation with a grain of salt—it does not provide any assurance that the "Mainstream" product will be compatible with OSs released later in the product's life cycle.

Most commercial software vendors prefer to wait until a feature-complete version of the OS is ready—an event that occurred late in the Windows Server 2008 release cycle—before they begin testing and building updates for their products.

Organizations can begin to evaluate and deploy the OS for nonapplication servers, such as file servers, domain controllers, and network infrastructure such as Dynamic Host Configuration Protocol or Domain Name System servers, while performing their application compatibility testing or waiting for supported software. Customers can also consider running these services on the new Server Core installation of Windows Server 2008. By the time this first round of evaluation and deployment is complete, more compatible application versions should be available.

Availability and Resources

A management and security product roadmap for compatibility with Windows Server 2008 appeared in "Management, Security Products Need Updates for New OS" on page 21 of the Apr. 2008 Update.

A description of Microsoft server applications that are supported on Windows Server 2008 is available at support.microsoft.com/kb/948680.

Resources for developers designing applications for Windows Server 2008 are located at msdn2.Microsoft.com/en-us/windowsserver/default.aspx.

The Application Compatibility Toolkit Version 5.0, which includes the Standard User Analyzer tool, is part of the Microsoft Deployment Toolkit 2008 (the next version of Business Desktop Deployment 2007). It can be downloaded by searching for "Microsoft Deployment Toolkit" at the Microsoft download center, www.microsoft.com/downloads.

The Works with Windows test tool, which measures an application's compliance with the Windows Server Logo requirements, can be a useful tool for testing application compatibility. It can be downloaded from www.innovateon.com/product_server2008.aspx.

The comprehensive list of tested hardware and software solutions for Windows Server 2008 is available at www.windowsservercatalog.com.

Background on Windows Server 2008 Server Core installation is available in "Server Core May Impact Infrastructure" on page 5 of the May 2007 Update.

Information on alternatives to the FrontPage Extensions are described at blogs.iis.net/robert_mcmurray/archive/2007/2/8/1570424.aspx.

A version of WebDAV or FrontPage Extensions for Windows Server 2008 can be downloaded from www.iis.net.

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