Achieve 99.999% Uptime
Datacenter Edition is more than just a fancy repackaging of Windows Server 2003. It's only available as part of a hardware and software bundle that puts a Windows mainframe into your data center.
For This Solution: Windows Server 2003, Datacenter Edition, Windows Server System, Specialized Hardware
The five nines. In the industry, this means 99.999 percent availability for a service, which translates to less than 5 minutes, 15 seconds of downtime per year. That's a little more than 26 seconds per month or less than 7 seconds per week. That's a tall order, but one that is often a core requirement for some of the most advanced Information Technology implementations that run key applications. You wouldn't want your bank to shut down on a regular basis would you? What about the government? What about your own organization? Do you have critical applications that need this level of service? Now comes the $20 million question: Would you try to achieve 99.999 percent uptime on Windows (see Table 1)?
Microsoft believes you can. That's why the company built the least-known member of the Windows Server 2003 family: Datacenter Edition. Datacenter is more than just another edition of Windows. It's a special original equipment manufacturer (OEM) version that is only available as part of a hardware and software bundle that basically puts a Windows mainframe class computer into your data center. This is a serious program as is evidenced by the OEM partners Microsoft lined up. These include mainframe heavyweights such as IBM, Fujitsu, HP, and Unisys. And that's just for the 32-bit version of Datacenter. The 64-bit version includes several additional players such Bull, Dell, and NEC.
What makes Datacenter more robust than any other version of Windows is the hardware it runs on, along with special tweaks included in the operating system. A 32-bit Windows Datacenter Server can run with up to 32 microprocessors and up to 64 GB of RAM. A 64-bit version boosts that to 64 processors and 512 GB of RAM. To run Datacenter, you'll need a machine capable of supporting a minimum of eight processors, and that's for each single partition you run in your Windows mainframe.
Both the 32-bit and the 64-bit versions support up to eight-node server clusters, and the Non-Uniform Memory Access (NUMA) architectures. NUMA is a process whereby Datacenter can call upon a special memory allocation table called the Static Resource Affinity table that is generated by the hardware it runs on. This table lets Datacenter dynamically allocate memory to the appropriate processes through affinity, letting the operating system run more efficiently. NUMA is also supported by the Enterprise Edition of Windows Server 2003, but it is only in Datacenter hardware that you find direct support for this process.
In addition, Microsoft created the Windows System Resource Monitor. This free add-on to the Datacenter and Enterprise editions of Windows Server lets you control which processors your server can use and how much memory each of the applications running on your server can use. This gives you more control over the overall operation of your mainframe Windows machine.
The Ultimate Virtual Server
The Datacenter mainframe is a single machine that provides partitions, both hardware and software, to run instances of Windows. Each instance must have potential access to the minimum number of processors and a proper hardware configuration. A complete Datacenter Server can run multiple instances of Windows Datacenter Edition, forming clusters through partitions that are supported either by the hardware itself or by the special OEM software that is made available with the hardware. In addition, you can use Microsoft Virtual Server 2005 to run virtual instances of your servers. In fact, Datacenter Server could be the ultimate virtual machine server, letting you manage a completely malleable Windows environment. But, the purpose of moving to Datacenter is to consolidate and reduce administration efforts, so be mindful of the number of partitions you choose to run (see Figure 1).
You'll want to run enough to profit from Datacenter's innate clustering technologies, adding to the availability offered by the special hardware and the operating system itself, and making sure your applications are always up and running. Here, it will be essential to have a good understanding of the compatibility of the various software applications you want to run on each partition. Though OEM partners have their own sources for this, there seems to be no easily located public source for the various combinations of the different Windows Server System products you can and should run in each partition. Table 2 outlines the various services and functionalities available through both Windows Server and the Windows Server System stack along with their affinities for each other. Affinities are based on the product or feature's support for the clustering technologies built into the operating system. It should provide valuable assistance in your decision-making process.
Base your product integration or consolidation project on the following rules:
1. Any product or component that is compatible with the Server Cluster Service inherent in Windows Server 2003, or any component that is server cluster aware, can reside on the same server or on the same server cluster node. This means you could create a Datacenter cluster running any one of the following with few compatibility issues:
- BizTalk 2004 Server State and Message Box Servers
- Distributed File System
- Dynamic Host Configuration Protocol and Windows Internet Naming Service
- Distributed Transaction Coordinator
- Exchange Server Message Stores
- File Sharing
- Identity Integration Server
- Microsoft Message Queuing
- Print Services
- Systems Management Server 2003
- SQL Server 2000 (and therefore any of the other product's database components)
- Terminal Services Licensing and the Session Directory Server
2. The same applies to any component supporting the Network Load Balancing Service. This means that your Network Load Balancing (NLB) cluster hosts could run any one of the following:
- BizTalk 2004 non-message processes
- Commerce Server Web components
- Content Management Server 2002 front-end and authoring servers
- Exchange Server 2003 front end and/or Outlook Web Access
- Internet Information Services 6.0
- Internet Security and Acceleration Server 2004
- Project Server 2003 Web Access and base services
- SharePoint Portal Server 2003 Web front-end servers, indexing and search, job servers
- Speech Server 2004
- Windows SharePoint Services
- Terminal Services sessions
3. Conversely, you should not run anything that is cluster independent on a cluster. Most products or technologies that are cluster independent are so because they include their own strategy for failover and availability. Active Directory is a prime example.
4. You should never try to combine the Microsoft Cluster Service with the Network Load Balancing Service.
5. You should always take the security aspects of any product combination in consideration, especially for NLB clusters. For example, though you can run it with other products, you should isolate Internet Security and Acceleration Server from any other products or components because of its very nature.
This makes a very strong case for product integration into a single coherent datacenter. Of course, you should test every single combination you want to implement thoroughly and then test it again to make sure you will get the availability levels you are looking for.
Choose Your Datacenter Server
Buying a Datacenter Server is not a simple process. First you have to find the right partner, and then choose the right class of hardwarethe latter is not too complex because most OEM partners only offer Datacenter on one or two classes of machines. However, that's only the start of the process. Once you've selected your partner and your hardware, you need to determine which services or applications you plan to migrate to the Datacenter Server. Most OEM partners have a specific process and special tools to help you do this. They are designed to take a complete inventory of all of your Windows systems and outline the system's utilization over time. One major justification for the move to Datacenter is server consolidation. If you have a number of smaller class machines all operating at less than their potential resources, you could stand to gain much by migrating them to a single Windows mainframe. The key here is to ensure your partner gives you a proper return-on-investment analysis before you make the leap.
A second key factor is determining which applications you intend to run on the Datacenter. Because availability and uptime are the core reasons for moving to a Datacenter Server, you want to make sure your system won't be struck down by a misbehaving application. That's why you need to select applications that have passed the testthe Veritest test in this case (see Resources)and are certified to run properly on the Datacenter Edition of Windows Server 2003. There are still few applications that have made the grade; Microsoft itself only has five members of the Windows Server System approved for Datacenter: BizTalk Server 2004, Exchange Server 2003, Office SharePoint Portal Server 2003, Operations Manager 2001 with Service Pack 1, and SQL Server 2000 Enterprise Edition. More are coming, but testing is rigorous and time-consuming. That's why most Datacenter customers begin with core applications that are either based on Exchange or SQL Server.
Once you have selected the key applications for your platform and you've got the right hardware, what's next? That's when the testing begins. First is the Datacenter Hardware Compatibility Test (HCT). This test runs a comprehensive series of programs against your proposed hardware, operating system, and software configuration for 14 days. This tests kernel mode drivers, server configuration, all applications or components that require kernel mode access (as opposed to user mode), and the storage subsystem you've put in place. If your system passes a 14-day test without fail it's on its way to approval. This first test is serious. If you change anything in the configuration, anything, you'll have to run the test again for seven days without failure.
Next is the predeployment audit. This audit consists of running Datacenter's Configuration Audit Test tool on your system. This will document the configuration of the server as it has been initially installed. Microsoft recommends running this tool on a regular basis to ensure that you have a history of configuration changes in your system. Once your configuration has been fully documented, you move on to enter the High Availability Support program. This gives you access to the High Availability Resolution Queue that provides 24/7 joint hardware manufacturer and Microsoft support 365 days a year. This program has evolved since the Windows 2000 edition of Datacenter to provide a single location for joint support. Datacenter is also not implemented if you do not have a documented change management strategy, which includes a change control service. This will ensure that your Datacenter evolves properly, includes appropriate patches, and maintains its status as a qualified configuration on an ongoing basis.
Move on to the Five Nines
Each partner has its own implementation program (see the sidebar, "The Unisys Datacenter") and all are complete and comprehensive. They have to because Microsoft takes Datacenter seriously, as do the partners. Microsoft has a lot at stake when trying to prove the reliability of a Windows-based Datacenter, especially in light of the increasing number of attacks on its products. This is why moving to Windows Datacenter is like entering another world. In reality, you are entering the world of the mainframe where every process is controlled and nothing happens without a reason. Datacenter provides service levels in the five nines, but has yet to support the complete disappearance of the standalone server.
Most Datacenter customers today have migrated applications to this system, but have not moved toward the complete replacement of all Windows servers by one big machine. It is possible, but so far customers are reluctant to do so. This means that the Windows Datacenter can include a mainframe running core applications along with a few standalone servers running services such as Active Directory, Domain Name System, Microsoft Operations Manager, and so on.
But don't kid yourself. Given the proper configuration, Datacenter Server can replace all of your standalone servers and give you the performance and availability levels you used to get from character-based mainframes. This would let you manage a much more virtual and integrated Windows IT system, one that ensures all systems are go from day one and will continue to be so from then on. If you're tired of running multiple servers, sometimes in the multiple hundreds of servers, and you can locate them in a single data center, then Windows Server 2003, Datacenter Edition might be the right choice for you. At first look, it seems more expensive than what you've got, but don't discount it. In the end, your Datacenter solution might be considerably less costly than many single servers. Move over old-style mainframes, this is the age of the graphical mainframe.
About the Author
Danielle Ruest and Nelson Ruest, both Microsoft MVPs, are IT professionals focused on technologies futures. They are authors of multiple books, including "Microsoft Windows Server 2008: The Complete Reference" (McGraw-Hill Osborne Media, 2008), which focuses on building virtual workloads with Microsoft's new OS.