Upgrading to IIS 6

IIS 4 was available within Windows NT 4.0 Option Pack for both server and client installations. IIS 4.0 was probably the first version of IIS most people were exposed to as a Web serving solution. Although earlier versions than this exist, it's unlikely you will be using them. IIS 5.0 comes with Windows 2000 server and Professional products.

Upgrading from IIS 4 or IIS 5 to IIS 6 is not as complicated as you might think. The point is that you have to upgrade the operating system to Windows Server 2003?you can't install IIS 6 on your existing Windows NT 4.0 or Windows 2000 server installation.

Upgrades can be completed more or less directly, and they have a number of advantages, such as the capability to upgrade and convert settings directly without further intervention. In many respects, performing an upgrade is the easiest and most effective way of upgrading to IIS 6 without the complexities of the IIS Migration software.

Upgrading also means that sites, locations, static files, data files, and other additional components are kept on the machine; and in many cases, it should be a relatively simple case. What upgrading doesn't do is upgrade anything to do with your site's dynamic elements.

If you are using ASP or VisualBasic components to provide customized information, you're going to need to make some minor modifications to some scripts, depending on what features you have used?it's best to check each script after the upgrade.

Upgrade Compatibility

Your primary concern is going to be the support for the underlying operating systems of Windows Server 2003. The system requirements for Windows Server 2003 are more extensive than Windows NT 4.0, ideally requiring a Pentium III processor running at 500Mhz.

The upgrade paths for Windows Server 2003 Standard Edition are

• Windows NT 4.0 with Service Pack 5 or later

• Windows NT Server 4.0 Terminal Server Edition with Service Pack 5 or later

• Windows 2000 Server

For Windows Server 2003 Enterprise Edition, you can upgrade from

• Windows NT Server 4.0 with Service Pack 5 or later

• Windows NT Server 4.0 Terminal Server Edition with Service Pack 5 or later

• Windows NT Server 4.0 Enterprise Edition with Service Pack 5 or later

• Windows 2000 Server

• Windows 2000 Advanced Server

• Windows Server 2003, Standard Edition

In short, Windows NT 4.0 with Service Pack 5 or Windows 2000 Server platforms can be upgraded to the same platform (basic to Standard editions, or Advanced Server to Enterprise Edition) or better (basic to Enterprise Edition). Note, however, that you can't downgrade?that is, upgrade from Windows 2000 Advanced Server to Windows Server 2003 Standard Edition.

Also be aware that certain aspects of your Web site and system might not be upgradeable. In particular, custom ISAPI filters and some aspects of your ASP code might not transfer effectively over to your new system.

Upgrade Process

The upgrade process is normally as easy as inserting the Windows Server 2003 CD into your server while it's running and following the onscreen instructions. You can see an upgrade in process in Figure 7.3.

However, before you rush to find the installation CD, you need to perform a few bits of preparation:

• Back up your server. Make sure that you have a complete backup that could bring your server back into full service as quickly as possible just in case everything goes wrong.

• Create a separate backup copy of your Web site files, any additional scripts, ISAPI filters, and other components. This will help you move the site to another machine in case the upgrade doesn't work.

• Back up your metabase file. You can find the metabase.bin file in %systemroot%\system32\inetsrv.

Once you've got the backups (and it's probably a good idea to have backups of the backups), insert the Windows Server 2003 CD and follow the onscreen instructions. Be prepared to wait; the process for upgrading is slightly more complex than a new installation. Whereas a new installation might take 35?45 minutes, an upgrade on the same machine might take 45 minutes to an hour because the installer has to go through a number of checks and verifications to know how to proceed with the upgrade.

For IIS in particular, it will also have to convert the IIS metabase from its binary format into the new XML format and, in the process, translate and convert the Web site definitions and applications into the new model.

After the Upgrade

You are obviously going to notice a few changes, and you will need to make a number of changes after the upgrade process. These include

• Operating mode? IIS 4 installations will be set to execute in IIS 5 Isolation Mode, rather than Worker Process Isolation Mode. IIS 5 Isolation mode is less secure, so you might want to change this. However, doing so might break any applications that you are using, so make sure that you test the system thoroughly before changing over full time to the worker process model.

• IIS availability? If you hadn't made any changes to the default Web site in IIS 4 and IIS 5, IIS won't actually be installed at all during the upgrade. As part of the security implied by Windows Server 2003, default IIS installations are disabled. You probably won't encounter this on a machine that is being upgraded specifically to gain the facilities of IIS 6, but it might if you are upgrading a machine to take the role of a Web/application server.

• Installed Components? ASP and FrontPage will only have been installed and upgraded if you already have these components installed.

• Administration Web Site? The administration site in IIS 4 and IIS 5 will still be there within the default Web site, but it will have been disabled. If you need to have Web-based administration on your new site, you will have to separately install that component.

• Default Web site? The default Web site will still be available, but some of the sub-directories will have been disabled. The Administration site is one example; others include the IIS help (which has been moved to the main Windows help system) and the MSADC Data Connector virtual directory.

The remainder of your Web sites should exist as before, with all their settings and other details intact. Any application pools you had configured in either IIS 4 or IIS 5 will have replicated to an appropriate application configuration under IIS 6. You will have to manually configure these applications with corresponding application pools if you want to convert to the worker process model.