But what if those changes occur all at once? That's the scenario with Windows Server 2008 (WS2008). Formerly known as Longhorn, WS2008 is set to be released later this year. Just this week, Microsoft made available the Community Technology Preview of the operating system, which includes installation and some other options in addition to what is available in the Beta 3 release.

When it does become available, WS2008 will definitely have an impact on the infrastructure of most large companies, at least at some point.

The question is: how much of an impact will it have?

The answer depends greatly on when you start planning, how quickly you deploy and which WS2008 features you want to make part of your technology infrastructure.

For example, Continental Airlines is using a phased implementation strategy. The company started working with Microsoft early, testing the server operating system in the airline's own datacentres and evaluating the release in Microsoft test laboratories.

Continental travelled up to Microsoft's offices at the end of April and tested the schema extensions and deployment with Continental's main Active Directory database file. "We created our entire forest architecture in the lab," says Jason Foster, a systems architect and senior technology manager at Continental. A forest architecture is a type of networking model, in this case for Continental's Active Directory structure.

The key for Continental is that it will control which services it will deploy, and when.

"We are taking a phased implementation approach where Phase 1 is limited to 10 Active Directory domain controllers in the Houston data centre," Foster explains. "We feel that phasing in the technology helps absorb some of the exposure, while adding the 10 new servers to the infrastructure allows the existing Active Directory to provide authentication services uninterrupted," so the company's security exposure is limited as it begins rolling in the new operating system.

In addition to the phased approach he described, Foster plans to deploy the Read Only Domain Controller (RODC) capability right away in most of Continental's regional locations at airports and in its two primary datacentres in Houston and Charlotte, Continental will use RODC to enforce security policies in regional and remote offices and prevent unauthorised intrusions.

Meanwhile, Ward Ralston, a senior technical manager at Microsoft, downplays the coming datacentre infrastructure changes. He says that the system requirements for WS2008 are remarkably similar to those for Windows Server 2003, released in April 2003. He also says that, while WS2003 had unspecified "millions" of lines of code, WS2008 has only about 800,000. If anything, Ralston says, WS2008 will streamline IT operations with its new Server Core and PowerShell features, not add new complexity. Indeed, Foster says, some services, such as DNS, DHCP and file/print, will have little impact on datacentres.

Ralston's seems to be the minority view. Christopher Voce, an analyst at Forrester Research, says that because the new server architecture in WS2008 has many important benefits for large organisations, it's best to start planning for deployment now.

"There are a host of new enterprise-level features, a new emphasis on remote management and new security improvements," says Voce. "The new Server Core feature could change the way administrators do their job. Some features, like PowerShell, look like nothing more than a blinking cursor, yet will have a dramatic impact on IT. The main point is: Start testing now."

A second analyst agrees that early testing is key. "The more managers learn about how Windows Server 2008 works now, and what to expect when it is released, the better off they will be," says Brian Babineau, an analyst at Enterprise Strategy Group.

To help ease the deployment burden, here are eight steps to follow to prepare for the new release.

Step 1: Start testing Windows Server 2008 Beta 3

The most intuitive and important step is to download and install Windows Server 2008 Beta 3, which was released in April.

Testing should be conducted in a way that simulates the real production environment, not just a portion of the infrastructure, says Forrester's Voce. This is true whether your company uses 18 servers or 800.

Of course, deployment timelines will vary from organisation to organisation, Voce says. Some companies are planning to wait for the first service pack for Windows Server 2008, which might appear in late 2008 or 2009. Others will wait until Windows Server Virtualisation is released sometime in 2008 before they deploy the new server operating system. A third strategy involves hardware cycles for desktops as many large companies will not deploy Vista until the hardware catches up to the operating system, and some are following the same strategy with their servers.

Interestingly, Microsoft's Ralston suggests that many companies will deploy Windows Server 2008 as part of new server hardware rollouts. According to internal Microsoft research, he notes, only 10% of Microsoft customers deploy servers on existing hardware. This could mean that companies will opt to wait for budget approval and for new hardware offerings from Dell and Hewlett-Packard before rolling out WS2008.

In any deployment timeline scenario, beta testing can reveal technology incompatibilities in an enterprise setup, especially in cases involving remote management using the new PowerShell feature, Server Cores, which provide a stripped-down version of the operating system to improve performance, and new Terminal Services for mobile users who need to access mission-critical applications, says Voce. (In our recent review of Longhorn Beta 3, our reviewer called Server Core the "killer feature" of the new operating system.)

Step 2: Build a WS2008 deployment team

Beta testing can be an ad-hoc process. But as a more formal step, it is important to build a team that will specifically address WS2008 deployment strategy with members from all areas of IT, including networking, storage, applications and security. It is also important to include representatives of business units, facilities management personnel and company officers if possible.

"Dedicate a project team that can look at the new features of Windows Server 2008 and how they impact the existing infrastructure," says Enterprise Strategy Group's Babineau. "For example, there are some networking enhancements in the new OS and the project team should work with the networking admins to understand any impact or potential benefit. A cross-functional team can help leverage the new features of Windows Server 2008 and mitigate any risk. This also holds true for the storage teams that utilise servers for file share storage."

Step 3: Develop a 64-bit migration plan

Microsoft has been encouraging IT managers to think about a move to 64-bit computing for some time. Ralston says that Windows Server 2008 will be the last 32-bit server operating system that Microsoft releases, and he notes that it is important for customers to begin the 64-bit migration steps early to weed out incompatibilities with other servers that do not offer 32-bit as an option.

Forrester's Voce agrees that this is an important piece of work for most shops. "We've reached the ceiling of 32-bit applications, which date back all the way to the 486 processor," he says. "Microsoft Exchange 2007 is a 64-bit-only application because of the requirements in memory handling and running efficiently in a larger memory envelope. Exchange introduced safe sender lists and unified communications for large user bases" of 12,000 to 15,000 users in an Active Directory, "and it would just be inefficient in a 32-bit envelope. That's why it is so important to start qualifying applications for 64-bit."

Step 4: Take advantage of Microsoft's Technology Adoption Program

Continental Airlines partnered with Microsoft through the vendor's formal Technology Adoption Program (TAP), an invitation-only party for which not all customers will qualify.

But for those who can sign up, there are benefits. Continental tested, deployed and configured many WS2008 services in its own R&D lab. With TAP, Continental can communicate directly with Microsoft technical contacts and discuss inconsistencies in the code base with engineers.

"This testing, configuration, break and fix life cycle generates quality that enables Continental to confidently take Windows Server 2008 into production," says Foster. "Mitigating the risk in our lab, with our engineers, builds the technical competencies that set us apart from the industry."

Step 5: Thoroughly test critical applications for WS2008 stability

Part of the beta testing process should involve testing applications for stability under WS2008. One example of the importance of this step is how WS2008 changes Web applications. Microsoft says the .Net framework will be more robust, with a new control interface. depends on hosted applications to provide services to its end users and is already planning for WS2008. The new server operating system provides new services for application control, such as Automatic Space Load Randomization, a technique for controlling application memory usage. HostMySite data centre administrators have already started learning the interface for these controls, setting up clustered server farm environments and provisioning sites in Internet Information Services 7.0, which is part of Windows Server 2008.

"Since the .Net framework plays a vital role in Windows Server 2008, and is intertwined with the OS, coding in .Net for administrative tasks, such as provisioning, will become much more important," says Neil Heuer, chief technology officer at HostMySite. "From a Web application perspective, we suggest a move away from classic ASP to ASP.Net."

Step 6: Learn the intricacies of PowerShell now

Another relatively easy step in planning for Windows Server 2008 is to start testing PowerShell, which is currently available for download and testing with existing servers.

Although the command line interface is daunting, PowerShell affords new time-saving and error-reducing measures. Administrators can deploy a new employee account in Active Directory in just one command line, adding the employee to the correct user groups and configuring e-mail, rather than having to populate multiple fields like they must do now with Windows Server 2003.

Voce noted that while many companies will move to Windows Server 2008 for the 64-bit support and new security controls for domains, they will quickly see a better workflow and automation for data centre operations. Microsoft promises that System Centre Virtual Machine Manager (SCVMM) will provide more automated services as well, and it says SCVMM should ease the virtual server-management burden.

Functions that can be automated with SCVMM, according to a Microsoft spokeswoman, include bulk VMware to Microsoft file conversions and bulk physical to virtual (P2V) conversions for server consolidation.

"We are already working with PowerShell against our WS 20003 environment," says Steve Cole, lead system support specialist at Quixtar , a health and beauty retailer in Ada, Mich. "On our next revision of scripts for building and configuring our servers, we are using PowerShell. We hope for this initiative to be completed before the release of Windows Server 2008, so that we can use PowerShell scripts to completely set up and configure the Web servers."

Step 7: Use the Microsoft Windows Server Deployment Solution Accelerator

This autumn, Microsoft will release a more comprehensive deployment planning tool called Windows Server Deployment Solution Accelerator (WSDSA), which will be available through Microsoft's site. Similar to the Windows Vista tool for desktop deployment, known as Business Desktop Deployment 2007, the Windows Server 2008 kit will include white papers, e-learning material and software to help server administrators.

However, Microsoft has decided that it will not release details about WSDSA or make public any deployment-specific Web sites until after WS2008 is released to manufacturing, or just weeks prior to that time.

Step 8: Time your server virtualisation schedule

One of the decisions facing IT managers is whether, and how, to deploy Windows Server 2008 in a virtualised environment. For those companies planning to deploy Microsoft Windows Server Virtualization (WSV), the timing is especially critical. Microsoft has indefinitely delayed some of its planned server virtualisation features, including live migration and the ability to add storage and other hardware on the fly, and it pared processor support back to a maximum of 16 cores.

Microsoft's Ralston noted that development efforts for WS2008 and WSV are not specifically coordinated with each other, WS2008 will ship first. Voce says that WSV is likely to ship a few months after that.

This means companies may opt to wait until they can deploy WS2008 in a Microsoft virtualised environment, so testing and implementation planning for the operating system could easily be put off several more months until the WS2008 and WSV schedules can be synced with one another.

Hope for the best, prepare for the worst

In the end, even with a detailed deployment plan in place for the technology changes in Windows Server 2008, no infrastructure is immune from surprises. Part of the deployment process should involve disaster recovery planning. A new server operating system appears only once every five years or so, and a wise approach is to hope for success but plan for any mitigating circumstances, such as down time and other negative infrastructure surprises. The technology benefits will hopefully outweigh the disruption, even in the largest server environments.