Before
delving into ways to tweak Exchange Server 2010 performance, it is
useful to have an understanding of the performance improvements that
have been made since its predecessor, Exchange Server 2007. Although
some of these performance improvements are more noticeable than others,
Exchange Server 2010 has been designed to scale into the enterprise and
beyond. Even prior to its release, Exchange Server 2010 was used to host
literally millions of mailboxes via Microsoft’s Live@edu offering,
which provided email services to students and gave Microsoft an
impressive opportunity to load test Exchange Server 2010 in a real world
implementation.
Architectural Improvements
Like Exchange
Server 2007, Exchange Server 2010 is built on a 64-bit architecture.
This provides Exchange Server 2010 with scalability and performance that
was not available with 32-bit code. By eliminating the legacy
limitation of a 3GB memory space, the Exchange Server engine is able to
cache very large amounts of data. This means that Exchange Server is no
longer as limited by disk input/output (I/O) performance. When
configured with sufficient memory, Exchange Server 2010 can reduce its
disk I/O requirements by as much as 66% over the already impressive
numbers offered by Exchange Server 2007. This allows administrators to
be much more efficient in their use of disks. Given the impressive rate
of growth of capacity of hard drives as opposed to the fairly stagnant
growth of I/O capacity, Exchange Server 2010 continues to drive a
paradigm shift toward low cost direct attached disk.
The improved
internal architecture of Exchange Server 2010 also allowed Microsoft to
raise the limits on the number of databases that could be hosted by a
single Exchange server. Whereas Exchange Server 2003 was only capable of
a total of 20 databases (spread out across four storage groups) and
Exchange Server 2007 was able to host as many as 50 databases (spread
out across 50 storage groups), Exchange Server 2010 again raises the bar
by allowing for 150 databases, which are no longer tied to storage
groups. This again offers administrators greater flexibility in how they
design their Exchange Server 2010 servers, which can result in
increased performance if it is designed correctly.
Database Engine Improvements
Microsoft has continued
to make great strides with the JET database. JET is the database used
by Exchange Server 2010, as well as in previous versions of Exchange
Server, to store mailbox data and public folder data. In the latest
64-bit version of JET offered by Exchange
Server 2010, the JET engine is able to take advantage of the lift in
restrictions on memory space and it allows JET to allocate significantly
more cache for the Exchange Server store. This means that users have
access to more cache and this greatly increases the likelihood that data
requested by a user is already in memory and doesn’t have to be read
from disk. This results in quicker response times for the end users.
Similarly, the database page size in Exchange Server 2010 has been
increased from 8KB to 32KB. Although this might not seem significant,
the result is that more messages are able to fit into a single database
page and, as a result, the Exchange server uses fewer I/O operations to
gather the requested information. This helps to significantly reduce the
overall I/O requirements of the Exchange Server 2010 server.
Tip
To take best advantage
of the larger block size used by Exchange Server 2010 when accessing
databases, consider formatting hard drives that will host Exchange
Server 2010 mailboxes with a larger block size. This will reduce
fragmentation within the disk and will reduce overall I/O usage by
reducing the number of disk blocks that have to be read for each
transaction.
Exchange Server 2010
has an entirely new Store schema that is significantly flatter than the
Store schema used by Exchange Server 2007. The changes in the Store
schema allow for 100,000 items in a single folder within the mailbox as
opposed to 20,000 in Exchange Server 2007. While this will alleviate a
source of pain for many “power users,” it is still recommended to
encourage users to organize their mailbox and to delete unneeded items
in order to keep their performance as high as possible.
Exchange Server 2010 has
also made some changes to offer what’s called the Personal Archive.
This functionality creates a folder within the mailbox that is actually
located in a secondary mailbox. The functionality works very similarly
to the concept of opening 2 mailboxes simultaneously, which is a fairly
common situation for Executive Admins or for IT members who monitor a
common mailbox. By creating this secondary mailbox, Exchange Server 2010
is able to reduce the load on the more commonly accessed mailbox by
allowing a user to offload the bulk of their messages into an archive.
The user is still able to access all the messages, but the loads are
effectively separated from each other. Enabling this Personal Archive
also prevents the user from creating PST files, which can be a very
useful control for IT departments who need to control where potentially
sensitive email information is stored.
Transport Pipeline Improvements
The transport pipeline
refers to the collection of server roles as well as various queues,
components, and connections within Exchange Server that work together to
transport messages to the message categorizer in the Hub Transport
server. The job of this categorizer is to deliver mail to the
appropriate location within the Exchange Server environment. This
process has been greatly improved in Exchange Server 2010 and is able to
handle significantly more messages than earlier versions of Exchange
Server.
Exchange Server 2010
introduces the concept of cross premises mail routing, wherein an
Exchange Server 2010 environment can be built with a combination of
onsite servers combined with off premises hosted servers, all acting as
part of the same Exchange Server organization.
A very useful improvement
in the Hub Transport functionality is changes to appended disclaimers,
performed by Hub Transport rules. The improved disclaimers can now
support hyperlinks and images as well as accessing fields in AD to
populate the disclaimers. This is exceptionally useful for Exchange
Server 2010 organizations that span multiple countries. For example, the
European Union requires that email messages sent outside an
organization must contain the physical address of the sending company’s
offices. In Exchange Server 2007, this required the creation of multiple
disclaimers and required administrators to manage them such that they
were attached to the members of the correct offices. In Exchange Server
2010, a single disclaimer could be utilized that queried Active
Directory to find the appropriate office address to use in the
disclaimer.
Exchange
Server 2010 also introduces moderated transport, which allows Hub
Transport rules to enforce a workflow for various messages. This would
allow Exchange Server 2010 to provide process routing so that one or
more parties would have to approve messages before they got to their
final destination. This can be a very effective way to control the usage
of managed distribution groups.
Shadow redundancy is a new
feature introduced by Exchange Server 2010 that serves to ensure that
messages are correctly routed within an organization. When a message is
sent, it isn’t considered truly sent until there is a confirmation from
the next hop that the message was passed along. For example, if a
message leaves a mailbox server and reaches a Hub Transport server, the
mailbox server doesn’t consider the message sent until the Hub Transport
server tells it that it was successfully sent to the next hop. If, for
example, the Hub Transport server were to crash before it was able to
pass the message along, the mailbox server would see that it never got a
confirmation that the message left the Hub Transport server and it
would resend the message via another Hub Transport server, assuming one
were available, and would wait for the next hop confirmation. This
prevents messages “in flight” from being lost due to a hardware or
storage failure.
Exchange Server 2010
also introduces a feature called MailTips. MailTips present the user
with useful information that will potentially change the way they send
messages. MailTips give administrators a way to warn users about the
action they are about to perform. For example, if a user is sending to a
distribution list, the MailTips will tell the user the number of
recipients that are about to get the message. In many cases, users don’t
necessarily understand the scope of a DL that they are about to use. By
knowing the actual audience, they may think twice about sending that
email about having kittens to give away. The MailTips can also give
users “what if” types of information. For example, if a user were typing
an email to a user who is out of office, the MailTips would preview
that target user’s OOF message even before the first user sent a
message. This would often result in the first user not wasting the time
to type a message to a user that isn’t going to get it any time soon. It
would also reduce the number of messages waiting for the second user
upon their return.
Perhaps
the most useful feature of the MailTips is the ability for the Exchange
Server 2010 system to quickly identify a recipient that isn’t in the
organization and can alert users to this fact. By knowing that someone
in the “Reply All” is from outside their organization, users are less
likely to include information that isn’t supposed to be told to people
outside the organization.
Security Improvements
Exchange Server
2010 has offered administrators greater integration with Rights
Management Services by allowing one to create Hub Transport rules that
will enable RMS protection on messages. This is a huge boon to
administrators as traditionally the biggest challenge with RMS is
getting employees to actually use it. By triggering the use of RMS based
on text patterns or on specific recipients, RMS can be activated
automatically.
Exchange Server
2010 also offers much more granular control in the area of delegating
permissions within Exchange Server. This should simplify the adoption of
role based administration with Exchange Server 2010.
Accessibility Improvements
Lack of support for
non-Internet Explorer browsers for use with OWA has long been a
complaint of Exchange Server administrators. While OWA works in other
browsers, it was always a neutered set of functionality with a less than
impressive appearance. Exchange Server 2010 has finally overcome that
limitation and now offers the full experience to all browsers. This will
allow Exchange Server administrators to overcome a large adoption
hurdle by finally being able to fully support Macintosh and Linux
clients as well as PC users that prefer to use web browsers other than
Internet Explorer.
Exchange Server
2010 has also introduced support for Text messaging (SMS) integration.
This allows Outlook Web App users to send SMS messages to phones.
The new Conversation View
allows email messages to be grouped together as a logical conversation
thread even if the messages are currently stored in different folders.
This simplifies tracking information in a conversation where some
participants might delete portions of the thread.
