Managing the Migration Process

Roll out the New System

Before making the new system available to all prospective users, you can use the checklist in Table 2.12 to verify that you’ve completed the minimum set of tasks required for a successful rollout.

Table 2.12 Rollout Checklist

	Task	Reference
	Migrate server configuration settings.	Migrating a Web Server to IIS 5.0 in this book.
	Migrate Web and FTP site content.	Migrating a Web Server to IIS 5.0 in this book.
	Migrate Web applications.	Migrating a Web Server to IIS 5.0 in this book.
	Prepare the network including implementation of a valid Windows 2000 Server domain and network topology.	Windows 2000 Server online product documentation.
	Install administrative tools and utilities.	Migrating a Web Server to IIS 5.0 in this book.
	Implement required policies and procedures.	Standards earlier in this section.
	Install tools, utilities, and applications needed by Web developers and end users.	Migrating a Web Server to IIS 5.0 in this book.
	Thoroughly test components, system, pages, and applications.	Validate the Design earlier in this section.
	Provide training on the new system for all administrators, developers, and end users.	Staff earlier in this section.
	Make technical support available for all users.	Staff earlier in this section.

Once you’ve completed the rollout checklist, you’re ready to make the new IIS 5.0 server available to users on the network. For a large-scale migration, or one involving mission-critical applications, you might deploy the server in steps, making its services available to progressively larger groups of users over time. For an example of how to do this, see the sidebar Testing at microsoft.com earlier in this section.

There are several technical approaches to taking a production Web server out of service and bringing the new server onto your network to begin hosting. The method you choose should be based on your network policies, amount of acceptable downtime, and your technical knowledge. Here are two possible methods:

If some downtime is acceptable, power down the existing production Web server and simultaneously start up the new IIS 5.0 server using the IP address and network settings of the existing production Web server. You might experience several minutes of server downtime; however, problems should be minimized if you perform the switch during off-peak hours and inform users several days in advance.
If no downtime is acceptable, assign the new IIS 5.0 server a new IP address, and set the transistor-transistor logic (TTL) units in the Domain Name System (DNS) records so that they will expire in 24 hours. Set up round-robin DNS so requests will be sent sequentially to the production Web server and to the new IIS 5.0 server. Wait for the DNS to propagate. After the first propagation, turn off the round-robin setting on the production Web server, and wait for propagation to occur again. When you’re sure the new IP has been propagated, turn off the production Web server. However, exercise caution if you’re using tracking or dynamic capabilities on your site, as problems could occur.
Of course, if you’re using a server clustering tool such as Network Load Balancing, all you need to do is assign the new server the appropriate IP address and bring it onto the network, and then take the old production Web server offline.