The
majority of capacity analysis is working to minimize unknown or
immeasurable variables, such as the number of gigabytes or terabytes of
storage the system will need in the next few months or years, to
adequately size a system. The high number of unknown variables is
largely because network environments, business policy, and people are
constantly changing. As a result, capacity analysis is an art as much as
it involves experience and insight.
If you’ve ever found yourself
having to specify configuration requirements for a new server or having
to estimate whether your configuration will have enough power to
sustain various workloads now and in the foreseeable future, proper
capacity analysis can help in the design and configuration. These
capacity-analysis processes help weed out the unknowns and assist you
while making decisions as accurately
as possible. They do so by giving you a greater understanding of your
Windows Server 2008 R2 environment. This knowledge and understanding can
then be used to reduce time and costs associated with supporting and
designing an infrastructure. The result is that you gain more control
over the environment, reduce maintenance and support costs, minimize
firefighting, and make more efficient use of your time.
Business depends on
network systems for a variety of different operations, such as
performing transactions or providing security, so that the business
functions as efficiently as possible. Systems that are underutilized are
probably wasting money and are of little value. On the other hand,
systems that are overworked or can’t handle workloads prevent the
business from completing tasks or transactions in a timely manner, might
cause a loss of opportunity, or keep the users from being productive.
Either way, these systems are typically not much benefit to operating a
business. To keep network systems well tuned for the given workloads,
capacity analysis seeks a balance between the resources available and
the workload required of the resources. The balance provides just the
right amount of computing power for given and anticipated workloads.
This concept of balancing
resources extends beyond the technical details of server configuration
to include issues such as gauging the number of administrators that
might be needed to maintain various systems in your environment. Many of
these questions relate to capacity analysis, and the answers aren’t
readily known because they can’t be predicted with complete accuracy.
To lessen the burden and
dispel some of the mysteries of estimating resource requirements,
capacity analysis provides the processes to guide you. These processes
include vendor guidelines, industry benchmarks, analysis of present
system resource utilization, and more. Through these processes, you’ll
gain as much understanding as possible of the network environment and
step away from the compartmentalized or limited understanding of the
systems. In turn, you’ll also gain more control over the systems and
increase your chances of successfully maintaining the reliability,
serviceability, and availability of your system.
There is no set or formal way
to start your capacity-analysis processes. However, a proven and
effective means to begin to proactively manage your system is to first
establish systemwide policies and procedures. Policies and procedures,
discussed shortly, help shape service levels and users’ expectations.
After these policies and procedures are classified and defined, you can
more easily start characterizing system workloads, which will help gauge
acceptable baseline performance values.
The Benefits of Capacity Analysis and Performance Optimization
The benefits of
capacity analysis and performance optimization are almost inconceivable.
Capacity analysis helps define and gauge overall system health by
establishing baseline performance values, and then the analysis provides
valuable insight into where the system is heading. Continuous
performance monitoring and optimization will ensure systems are stable
and perform well, reducing support calls from end users, which, in turn,
reduces costs to the organization and helps employees be more
productive. It can be used to uncover
both current and potential bottlenecks and can also reveal how changing
management activities can affect performance today and tomorrow.
Another benefit of
capacity analysis is that it can be applied to small environments and
scale well into enterprise-level systems. The level of effort needed to
initially drive the capacity-analysis processes will vary depending on
the size of your environment, geography, and political divisions. With a
little up-front effort, you’ll save time, expense, and gain a wealth of
knowledge and control over the network environment.
Establishing Policy and Metric Baselines
As mentioned earlier, it
is recommended that you first begin defining policies and procedures
regarding service levels and objectives. Because each environment varies
in design, you can’t create cookie-cutter policies—you need to tailor
them to your particular business practices and to the environment. In
addition, you should strive to set policies that set user expectations
and, more important, help winnow out empirical data.
Essentially, policies and
procedures define how the system is supposed to be used—establishing
guidelines to help users understand that the system can’t be used in any
way they see fit. Many benefits are derived from these policies and
procedures. For example, in an environment where policies and procedures
are working successfully and where network performance becomes
sluggish, it would be safe to assume that groups of people weren’t
playing a multiuser network game, that several individuals weren’t
sending enormous email attachments to everyone in the Global Address
List, or that a rogue web or FTP server wasn’t placed on the network.
The network environment is
shaped by the business more so than the IT department. Therefore, it’s
equally important to gain an understanding of users’ expectations and
requirements through interviews, questionnaires, surveys, and more. Some
examples of policies and procedures that you can implement in your
environment pertaining to end users could be the following:
Email message size, including attachments can’t exceed 10MB.
SQL Server databases settings will be enforced with Policy Based Management.
Beta
software, freeware, and shareware can be installed only on test
equipment (that is, not on client machines or servers in the production
environment).
Specify what software is allowed to run on a user’s PC through centrally managed but flexible group policies.
All computing resources are for business use only (in other words, no gaming or personal use of computers is allowed).
Only business-related and approved applications will be supported and allowed on the network.
All home directories will be limited in size (for example, 500MB) per user.
Users
must either fill out the technical support Outlook form or request
assistance through the advertised help desk phone number.
Policies
and procedures, however, aren’t just for end users. They can also be
established and applied to IT personnel. In this scenario, policies and
procedures can serve as guidelines for technical issues, rules of
engagement, or an internal set of rules to abide by. The following list
provides some examples of policies and procedures that might be applied
to the IT department:
System backups
must include System State data and should be completed by 5:00 a.m. each
workday, and restores should be tested frequently for accuracy and
disaster preparedness.
Routine
system maintenance should be performed only outside of normal business
hours, for example, weekdays between 8:00 p.m. and 12:00 a.m. or on
weekends.
Basic technical support requests should be attended to within two business days.
Priority technical support requests should be attended to within four hours of the request.
Any
planned downtime for servers should follow a change-control process and
must be approved by the IT director at least one week in advance with a
five-day lead time provided to those impacted by the change.
Benchmark Baselines
If you’ve begun defining
policies and procedures, you’re already cutting down the number of
immeasurable variables and amount of empirical data that challenge your
decision-making process. The next step to prepare for capacity analysis
is to begin gathering baseline performance values. The Microsoft
Baseline Security Analyzer (MBSA) is an example of a tool that performs a
security compliance scan against a predefined baseline.
Baselines give you a
starting point with which you can compare results. For the most part,
determining baseline performance levels involves working with hard
numbers that represent the health of a system. On the other hand, a few
variables coincide with the statistical representations, such as
workload characterization, vendor requirements or recommendations,
industry-recognized benchmarks, and the data that you collect.
Workload Characterization
Workloads are defined by how
processes or tasks are grouped, the resources they require, and the type
of work being performed. Examples of how workloads can be characterized
include departmental functions, time of day, the type of processing
required (such as batch or real-time), companywide functions (such as
payroll), volume of work, and much more.
It is unlikely that each system
in your environment is a separate entity that has its own workload
characterization. Most, if not all, network environments have systems
that depend on other systems or are even intertwined among different
workloads. This makes workload characterization difficult at best.
So, why is workload
characterization so important? Identifying systems’ workloads allows
you to determine the appropriate resource requirements for each of them.
This way, you can properly plan the resources according to the
performance levels the workloads expect and demand.
Benchmarks
Benchmarks
are a means to measure the performance of a variety of products,
including operating systems, virtually all computer components, and even
entire systems. Many companies rely on benchmarks to gain competitive
advantage because so many professionals rely on them to help determine
what’s appropriate for their network environment.
As you would suspect,
Sales and Marketing departments all too often exploit the benchmark
results to sway IT professionals over their way. For this reason, it’s
important to investigate the benchmark results and the companies or
organizations that produced the results. Vendors, for the most part, are
honest with the results, but it’s always a good idea to check with
other sources, especially if the results are suspicious. For example, if
a vendor has supplied benchmarks for a particular product, check to
make sure that the benchmarks are consistent with other benchmarks
produced by third-party organizations (such as magazines, benchmark
organizations, and in-house testing labs). If none are available, you
should try to gain insight from other IT professionals or run benchmarks
on the product yourself before implementing it in production.
Although some suspicion
might arise from benchmarks because of the sales and marketing
techniques, the real purpose of benchmarks is to point out the
performance levels that you can expect when using the product.
Benchmarks can be extremely beneficial for decision making, but they
shouldn’t be your sole source for evaluating and measuring performance.
Use the benchmark results only as a guideline or starting point when
consulting benchmark results during capacity analysis. It’s also
recommended that you pay close attention to their interpretation.
Table 1
lists companies or organizations that provide benchmark statistics and
benchmark-related information, and some also offer tools for evaluating
product performance.
