In-Depth

Get It Together

Server consolidation conjures up dreams of easier management for admins, but scaling the barriers to achieve it can bring you back to reality. Here's how to tackle the challenge head-on.

• By Danielle Ruest and Nelson Ruest
• 02/01/2005

You'll have to craft a carefully considered consolidation plan that addresses both procedural and technological concerns, choose the best technologies to accomplish the task and determine which services you plan to consolidate and where. You'll have to sell the plan to both your executives and to your user community. By formulating a clear and sensible plan and properly communicating that plan up and down the ladder, you'll give yourself the best chance for success.

The challenges with consolidation are twofold. The first part is political and financial. People simply don't want to share their servers with other groups. Most of the time, new servers are funded by specific projects. You have to put a new service in place, so why not get a new server at the same time? Many organizations also fund projects as a whole, combining all costs for resources, software and hardware. While this approach has merit, it leads to a proliferation of underutilized servers.

To resolve this problem, organizations should deal with IT as a service, especially when it involves server capacity. Project budgets should include provisions for server hardware and software costs, but instead of reflexively using that funding to purchase new servers on a project-by-project basis, the company should refer to IT to provide the service. IT could then use the budget to pay for sufficient server capacity, whether that means an entirely new server or more efficient use of existing servers.

The second consolidation challenge is technological. With Windows NT, for example, IT professionals preferred to isolate network services. Though it was a true 32-bit operating system, NT tended to be a bit single-minded and didn't always behave well with multiple services installed. This led to a proliferation of NT servers, all running at 10 percent to 15 percent capacity.

Regardless of which operating system your servers are running, consolidation is typically easier when you stay within the same server function. If you had 20 file servers, for example, you may be able to reduce that number to five or six. If you had 20 print servers, you may be able to cut down to four or five. Even then, when you have regional servers providing local services, you can't expect to replace them with a central server without upgrading your communications infrastructure. After upgrading your wide area network (WAN), you still have to ensure that services are available in the event of WAN service outages.

With the right combination of operating systems, such as Windows XP and Windows Server 2003, you can centralize file services if you activate offline file and folder storage. Clients can then continue to work even if the WAN is out because everything is also stored locally on their hard drives. This doesn't help when you centralize print services, however. With a WAN outage, regional users won't have access to the central print queue. So be careful when choosing which services to consolidate.

That problem is compounded when you try to consolidate several different services on the same server. Take the Windows Server System stack, which provides messaging through Microsoft Exchange, instant messaging through Live Communications Server, relational database through SQL Server 2003 and so on. How do you decide which services you can host on the same server in the same stack? Microsoft doesn't provide much guidance in this regard.

Figure 1. Services running on a single-node cluster can use the same name as a legacy server, making the consolidation transparent to users. (Click image to view larger version.)

Consolidate by Clustering
It's best to use the latest technologies for effective consolidation, like Windows Server 2003 server operating system, which is designed to scale better and support larger workloads. That doesn't mean you need to move your entire server infrastructure to Windows Server 2003, only the portions you need to consolidate. Despite the recent security issues with the Windows operating systems, Windows Server 2003 has a better track record than any other Windows OS to date.

Windows Server 2003 supports a most unusual service that can help an organization's consolidation efforts—the single-node cluster. This means you can use the clustering service in Windows Server 2003 to create "fake" clusters on a single server with virtual server technology. There are several reasons an IT organization might want to do this.

First, the Microsoft Cluster Service (MSCS) in Windows Server 2003 uses virtual server names to represent a service to the network (see Figure 1). These can be any valid server name. For example, if you have an NT server running at 10 percent to 15 percent of its total capacity, move the services running on that server to a single-node cluster on another server, create a virtual name to represent the old server, and run the service. You won't have to do any modifications to client computers and the migration will be completely transparent to your users. You can do this with a number of different services and run the server that is actually hosting them until it reaches 50 percent utilization or an acceptable performance level.

Second, MSCS runs on either small computer system interface (SCSI) or Fibre Channel connections to shared disks. MSCS can support up to two-node clusters when connected with SCSI, but it can go up to eight nodes when connected with Fibre Channel. If you don't have the budget for Fibre Channel connections initially, you can still create a single-node cluster with SCSI. This way, you can use the less expensive technology and you'll be ready to add a second node when demand for the service grows (see Figure 2).

Figure 2. Clustered servers expand differently depending on which network technology you use. If you use a SCSI connection, you can expand your cluster to two nodes. With Fibre Channel, you can expand up to eight nodes.

Third, because it's easy to use the clustering service in Windows Server 2003, you should use it by default whenever you put a specific service up on your network. Besides ensuring increased uptime, using clustering services means no service outage when you need to apply patches or update system software. This alone can make it worthwhile. The Enterprise Edition of Windows Server 2003 installs MSCS by default.

You can also use virtualization technology, either Microsoft Virtual Server 2005 or VMware GSX Server 3.1, to run competitive services in different instances of the operating system on the same physical hardware. Each instance of the OS is seen as a separate machine by the virtualization service, so there is no competition for resources. Another great consolidation support tool is the Windows System Resource Manager, a free add-on that lets you monitor and allocate resources to different services running on either the Enterprise or Datacenter edition of Windows Server 2003.

Choose Your Service
Though Microsoft doesn't provide specific information on which services to consolidate on which servers, it does offer some general advice. It has a nine-step consolidation strategy that runs you through the standard steps of assessment, project goal identification, architectural design, deployment planning, pilot testing, deployment strategy finalization, implementation, user migration and migration review. (For Microsoft's strategy, plus other consolidation resources, click here.) There's nothing new here, especially if you're familiar with migration projects, but it does provide some guidance.

Figure 3. Clustered servers expand differently depending on which network technology you use. If you use a SCSI connection, you can expand your cluster to two nodes. With Fibre Channel, you can expand up to eight nodes. (Click image to view larger version.)

Microsoft generally recommends consolidation in the following areas (see Figure 3):

• File and print, because they are non-competitive services.
• Web and application servers, especially using IIS 6.0 because it supports the isolation of Web sites on the same machine.
• Messaging with Exchange Server 2003, because it can store multiple storage groups on the same machine and can handle many more clients than previous versions (for more on Exchange consolidation see "E-mail Central").
• Database services, because SQL Server 2000 can run up to 16 instances on the same physical server.

A Singular Goal
The goal of server consolidation is simple—to manage fewer servers. Tell yourself that with each new project, especially those requiring new hardware, you'll use the budget to provide the server capacity and not automatically add additional servers.

Prove to your superiors that server consolidation does work and that you can run servers at 50 percent or more of their capacity. Make notes, record the appropriate data on performance and uptime, and when you're ready, present it to the powers that be (see "Consolidation: Step-by-Step"). This should go a long way toward proving that consolidation is the right thing to do—and it should help dispel those political, cultural and financial barriers.

[This article was originally published as "You're Fired," in Redmond Magazine, October 2004.—Editor]