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.
Consolidation is an IT administrator's dream. Simplicity, fewer servers
to manage and fewer licensing fees are all compelling reasons to consolidate.
Still, server consolidation is not without its hardships and difficult
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
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
To resolve this problem, organizations should deal with IT as
a service, especially when it involves server capacity. Project
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,
that means an entirely new server or more efficient use of existing
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
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
offline file and folder storage. Clients can then continue to
work even if the WAN is out because everything is also stored
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
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
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
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.
have an NT server running at 10 percent to 15 percent of its
total capacity, move the services running on that server to
cluster on another server, create a virtual name to represent
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
up to two-node clusters when connected with SCSI, but it can
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.
Use the following steps to launch your first consolidation
project and prove the value of consolidation to your peers and superiors.
Identify the appropriate candidates for consolidation.
These should be mostly legacy servers—NT or Windows 2000—that
are running at 15 percent to 25 percent of capacity.
Establish a single-node cluster with Windows
Server 2003, Enterprise Edition. Be careful of the technology
you use to connect to shared resources because it will impact
the future growth of your cluster. If you don’t intend to grow
the cluster and only want to virtualize servers, you can use
direct-attached storage for the single-node cluster.
Move the services to the single-node cluster
and use a virtual legacy server name to enable the service.
This process will be transparent to users.
Keep the legacy server on standby in case of
problems. It will serve as your fallback strategy.
Monitor server performance statistics and usage
data for a couple of months.
Prepare a usage and performance report that
will be easy for your peers and superiors to understand and
Present your case for consolidation, and prevent
— Danielle and Nelson Ruest
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
|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
clients than previous versions (for more on Exchange consolidation
- 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,"
Magazine, October 2004.—Editor]