Examining Exchange Server 2010 Performance Improvements

2/12/2011 3:10:33 PM
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.


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.

  •  Recovering from a Disaster in an Exchange Server 2010 Environment : Recovering Active Directory
  •  Business Intelligence in SharePoint 2010 with Business Connectivity Services : External Content Types (part 3) - Creating an External Content Type for a Related Item
  •  Business Intelligence in SharePoint 2010 with Business Connectivity Services : External Content Types (part 2) - Defining the External Content Type
  •  Business Intelligence in SharePoint 2010 with Business Connectivity Services : External Content Types (part 1)
  •  Recovering from a Disaster in an Exchange Server 2010 Environment : Recovering from Database Corruption
  •  Recovering from a Disaster in an Exchange Server 2010 Environment : Recovering Exchange Server Application and Exchange Server Data
  •  Recovering from a Disaster in an Exchange Server 2010 Environment : Recovering from a Complete Server Failure
  •  Sharepoint 2007: Add a Column to a List or Document Library
  •  Sharepoint 2007: Create a New Document Library
  •  Sharepoint 2007: Open the Create Page for Lists and Libraries
  •  Exchange Server 2010 : Developments in High Availability (part 3) : Backup and restore
  •  Exchange Server 2010 : Developments in High Availability (part 2) : Configuring a Database Availability Group & Managing database copies
  •  Exchange Server 2010 : Developments in High Availability (part 1) : Exchange database replication & Database Availability Group and Continuous Replication
  •  High Availability in Exchange Server 2010 : Exchange Server database technologies
  •  SharePoint 2010 : Cataloging the Best Scripts to Automate SharePoint Administration
  •  SharePoint Administration with PowerShell (part 2)
  •  SharePoint Administration with PowerShell (part 1)
  •  Sharepoint 2007: Approve or Reject a File or List Item
  •  Exchange Server 2007 : Configure the Client Access Server - Enable POP3 and IMAP4
  •  Exchange Server 2007 : Configure the Client Access Server - Enable and Configure Outlook Anywhere
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