Capacity
and performance analysis for an Exchange Server 2010 environment
requires a well-established understanding of the business and messaging
needs of the organization and a well-documented outline of the
organization’s expectations of its messaging environment. The capacity
of an Exchange Server environment is directly dependent on the expected
level of performance. It is important to understand exactly what it is
you are expecting
from the system in terms of storage per user, level of responsiveness
of the server, and room for anticipated expansion. When armed with these
concepts, you can more accurately determine what your current capacity
is.
The first step in
capacity analysis is to grasp an understanding of these concepts and
define performance expectations. This can be done by establishing
policies and service level agreements (SLAs). It is in these policies
and SLAs that an administrator can outline acceptable performance
thresholds and more accurately gauge the capacity needs of Exchange
Server 2010. These thresholds can also be used to accurately establish
performance baselines from which to analyze the requirements against
available resources.
To help develop the
policies and SLAs, use questionnaires, interviews, business objectives,
and the like along with performance measurements via the Performance
Monitor, Exchange Best Practices Analyzer, or third-party analysis
tools. This allows you to combine realistic expectations with concrete
data to see where you are relative to where you want to be.
Establishing Baselines
The
importance of establishing meaningful baselines of the messaging
environment cannot be underscored enough. Baselines are particularly
important in the sense that they are the measurable tools that can be
used to balance what is required of Exchange Server 2010 with what
resources are needed to fulfill those requirements. Achieving this
balance can be made simpler if an administrator consults performance
metrics, such as industry-standard benchmarks. By starting with an
accurate baseline of system performance, you can quickly and easily test
changes in the environment to see if they have made things better or
worse. Accurate baselines are also very helpful when troubleshooting
problems and you can quickly determine which subsystems are not
performing the way they normally do. A clear baseline allows you to
determine whether a server that “seems slow” really is slower than the
way it usually runs.
Note
Use ExchDump to assist
with baselining the environment. ExchDump exports a server’s
configuration, which can be useful to determine whether the build
follows company standards. This is particularly important with Exchange
Server clusters because each node in the cluster should be a replica of
the other.
To establish an
accurate baseline of Exchange Server 2010, a number of tools can help an
administrator in this process. These tools are discussed in detail in
the following sections. Some of these capacity analysis tools are built
in to Windows Server 2008, and others are built in to Exchange Server
2010. Many third-party tools and utilities are also available for the
careful measurement of Exchange Server 2010 capacity requirements and
performance analysis.
Using the Exchange Best Practices Analyzer Tool
The Exchange
Best Practices Analyzer (ExBPA) is a utility provided by Microsoft that
analyzes an Exchange server’s configuration and informs administrators
of possible configuration
changes that can be made to improve performance or mitigate problems.
More specifically, ExBPA can be used to perform a health check, a health
and performance check, a connectivity test, and a baseline test. This
tool, which was a download in previous versions of Exchange Server, is
now a built-in tool. To access the Best Practices Analyzer, perform the
following steps:
1. | Launch Exchange Management Console.
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2. | If the left pane, scroll down and select Toolbox.
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3. | In the center pane, double click Best Practices Analyzer.
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4. | When
the Best Practices Analyzer tool launches, check the Check for Updates
on Startup check box, and click Check for Updates Now. Joining the
Microsoft Customer Experience Improvement Program is optional.
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5. | If
there are updates available, click Download the Latest Updates. This
will ensure you have the latest version of the tool and any of the
latest updates to their configuration rules.
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6. | After being updated, the tool closes, and you have to click it again.
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7. | Choose Go to Welcome Screen.
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8. | Click Select Options for a New Scan.
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9. | Type the name of your closest global catalog, and click Connect to the Active Directory Server.
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10. | Enter a label for this scan, choose the systems you want to scan, choose Health Check, and click Start Scanning.
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11. | When the tool has finished, click View a Report of This Best Practices Scan.
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When viewing the report,
an administrator is able to see any critical issues, nondefault
settings, or recent changes to the system. This quickly identifies
configuration settings that might be detrimental to the overall
performance of the system. Be sure to always update the Best Practices
Analyzer before running it because Microsoft is constantly adding new
information to this tool.
The
Informational Items tab offers a convenient and consolidated view of
information that is typically captured in Exchange Server documentation.
Take advantage of this view when tracking the configuration of your
Exchange Server 2010 servers.
The Best Practices
Analyzer also allows administrators to run a multi-hour performance
baseline that serves as an excellent way to track overall changes in the
performance of servers. By looking at several hour blocks of time and
running the tool at the same time on the same day of the week,
administrators can get a very accurate view of how the loads on their
servers are affecting performance.
Planning for Growth
One of the easiest
ways to maintain the performance of an Exchange Server 2010 server is to
plan ahead for the growth of the environment. Too many administrators
have a tendency to build an Exchange Server infrastructure that meets
the storage and performance requirements of today but that fails to
account for the growth of the company.
Typically, when designing
an Exchange Server 2010 infrastructure, you should try to look ahead
roughly 3 years to predict the size to which the company will grow. This
is a good time to talk to groups such as Human Resources and Finance to
see the rate at which the company has grown historically. This will
give you a good idea of how many employees would be utilizing the
Exchange Server environment in 3 years. This process should also uncover
specific expansion plans for the company. For example, if the company
were going to grow from 10,000 employees to 13,000 employees in 3 years,
you would naturally consider that a 30% growth and would allow for an
extra 30% capacity on servers. However, if the case were that 2,000 of
those employees would be in a new facility in Japan that was going to be
online in 2 years, it would really be a 10% growth across the
enterprise and potentially a very large increase in capacity needs in
Asia or perhaps an entirely new Exchange Server site in Japan.
Understanding these
types of growth allow you to more easily plan for capacity growth and
understand how the increase in user load will affect the performance of
your Exchange Server 2010 servers in various sites.
The other thing to
consider when planning for growth is the increases in usage of the
Exchange Server environment. It is common to see companies increase the
storage limits for users without changing the number of users on a
server. There are also third-party technologies that might be in your
3-year plan that will leverage Exchange Server 2010 as a storage or
transport. Voice mail systems, Structured Query Language (SQL), or
Oracle implementations could quickly increase the loads placed on your
Exchange Server 2010 servers.
The reason it is important
to predict, as best you can, these anticipated growths is because it is
often easier to account for these needs at the time of the Exchange
Server 2010 design. Most companies are using storage area networks
(SANs) or network attached storage (NAS) for the mailbox stores in
Exchange Server. Although these systems do have the ability to resize
their LUNs to offer additional storage, this is a very time-consuming
process and it directly impacts the users on the server. Similarly,
because these are usually shared storage devices, there is likely not
enough spare capacity on the shelf or device to allocate more space to
the Exchange servers. This results in the SAN or NAS administrator
having to allocate additional space in a nonoptimal way, which can
affect the performance of all the applications that attach to the NAS or
SAN. That said, Exchange Server 2010 utilizing direct attached storage
can generally be expanded easily by simply adding more disks, assuming
the subsystem has room to allow for more disks. Based on this ability,
administrators should consider avoiding deploying all 100 databases on a
server from day 1.
