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Tools for Performance Stressing Exchange 2003 Servers


Topic Last Modified: 2006-03-09

By Nino Bilic

This article covers several tools that are now publicly available and can be used for performance stressing servers running Microsoft® Exchange Server 2003. This overview should help you in server stressing to gauge performance under heavy load.

Microsoft Exchange Server Load Simulator 2003 (LoadSim 2003) is a benchmarking tool designed to test how a server responds to mail load. LoadSim 2003 allows you to simulate the delivery of multiple MAPI client messaging requests to an Exchange server. To simulate the delivery of these messaging requests, you run LoadSim tests on client computers. These tests send multiple messaging requests to the Exchange server, thereby causing a mail load.

LoadSim 2003 can only run in domains in which Exchange Server 2003 has been installed. One reason for this is that LoadSim 2003 requires that the domain be updated with the Exchange Server 2003 schema. To use LoadSim with previous Exchange versions, use earlier versions of LoadSim, such as LoadSim 2000 for Exchange 2000 Server and LoadSim 5.5 for Exchange Server version 5.5.

LoadSim 2003 contains the following improvements, compared to earlier versions:

  • New user profile   LoadSim 2003 includes an additional client profile that simulates the tasks of Microsoft Office Outlook® 2003 users working in cached mode.

  • RPC over HTTP   LoadSim 2003 allows complete simulation of RPC over HTTP deployments. For example, you can use LoadSim to simulate RPC over HTTP in a deployment with Secure Sockets Layer (SSL) encryption enabled.

  • Outlook 2003 specific tasks   LoadSim 2003 allows you to simulate the new Smart Folders, Offline Address Book, and Synchronize Folders tasks to better simulate real-life users.

  • Query-based distribution group support   LoadSim 2003 supports the use of query-based distribution groups, which are sometimes referred to as Dynamic Distribution Lists, for sending mail in the topology.

  • Rules   LoadSim 2003 allows you to populate users with server-side rules and simulate how users create and delete them over time. All LoadSim-created rules are visible and capable of being manipulated by Outlook 2003.

  • Profile improvements   LoadSim 2003 enhances the simulation capabilities of the Medium and Heavy user profiles. These improvements to the Medium and Heavy profiles include keeping messages open and loading message properties in a consistent manner with Outlook 2003. Note that the MMB2 profile simulation capabilities were not enhanced in LoadSim 2003.

  • Individual logons   LoadSim 2003 simulates users logging on to their own mailboxes using their own accounts, known as per-user logon. By default, individual logons are used, instead of using the account LoadSim.

  • HTML bodies in messages   LoadSim 2003 simulates message bodies in HTML, which is the default format used by Outlook 2003.

  • Password setting   LoadSim 2003 includes a feature that allows you to specify a password used by your LoadSim users to log on to Exchange. You can use this feature to specify a password that meets your organization's security requirements. In addition, you can also reset that password at any time to meet your organization's requirements for password resets.

LoadSim 2003 is a tool that simulates the performance load of MAPI clients. It is a useful tool for administrators who are sizing servers and validating a deployment plan. Specifically, LoadSim helps you determine if each of your servers can handle the load to which they are intended to carry. Another use for LoadSim is to help validate the overall solution.

LoadSim should be used only in laboratories that have no connection to the production environment. This tool should not be used in any way in a production environment or an environment that is mission critical or contains important information of any kind anywhere in the network.
LoadSim will simulate only MAPI client load.

LoadSim creates numerous user mailboxes to create the simulated mailbox load. Because mailboxes must be part of a domain user's account, the LoadSim tool thus creates numerous domain user accounts to support these user mailboxes. Because the tool creates these accounts in bulk, it assigns the same password to all user accounts. Because this most likely does not conform to your organization's security requirements, to mitigate any risk this might present, we recommend that this tool only be used on isolated test networks that do not have connectivity to your production network.

Because load simulation works by consuming system resources, LoadSim is not appropriate for use on production networks, because it could interfere with production operations by competing for those resources. Because of this, the LoadSim tool should not be present on production systems.

You should know that LoadSim does not take all factors into account that are necessary to size servers completely. The following factors are not simulated by LoadSim and can impact your server capacity planning:

  • Incoming spam from the Internet.

  • Incoming Simple Mail Transfer Protocol (SMTP) mail flow from the Internet or other sites within your organization.

  • Use of non-MAPI protocols for account access. Examples include Post Office Protocol version 3 (POP3) and IMAP4.

  • Use of mobile devices.

  • Public folder utilization.

In addition, LoadSim does not provide complete information about the user experience, and its results should not be interpreted in that aspect. 

To download the LoadSim 2003 tool and other Exchange Server 2003 tools, see Downloads for Exchange Server 2003.

Note that there is a white paper included in the LoadSim package that discusses in detail how to configure LoadSim properly.

Microsoft Exchange Server 2003 is a disk-intensive application that requires a fast, reliable disk subsystem to function correctly. JetStress.exe (Jetstress) is a tool, designed by the Microsoft Exchange product group to help administrators verify the performance and stability of the disk subsystem prior to putting their Exchange server into production.

Jetstress helps verify disk performance by simulating Exchange disk I/O load. Specifically, Jetstress simulates the Exchange database and log file loads produced by a specific number of users. You use Performance Monitor, Event Viewer, and Exchange Server Database Utilities (Eseutil) with Jetstress to verify that your disk subsystem meets or exceeds the performance criteria you establish.

Jetstress allows you to perform two types of tests: the Jetstress Disk Performance Test and the Jetstress Disk Subsystem Stress Test. The Disk Performance Test runs for two hours and allows you to verify the performance and sizing of your storage solution. The Disk Subsystem Stress Test runs for 24 hours and allows you to test the server storage reliability over a more significant amount of time. Running both tests is the best way to verify the integrity and performance of your disk subsystem.

After a successful completion of the Jetstress Disk Performance Test and Disk Subsystem Stress Test in a non-production environment, you will be ready to move on to the next stage in your Exchange Server 2003 deployment process. You will have ensured that your Exchange Server 2003 disk subsystem is adequately sized, in terms of your performance criteria, for the user count and user profiles you have established.

Jetstress is only supported when running with Ese.dll associated with Exchange Server 2003 or Exchange 2000 Server. Also, due to this support limitation, Jetstress is only supported on Microsoft Windows Server™ 2003, Windows® 2000 Server, Windows 2000 Advanced Server, and Windows 2000 Datacenter Server. Windows NT® Server 4.0 and earlier operating systems are not supported.

This tool is intended only to simulate Exchange disk I/O activity. LoadSim lets you simulate network and client activity, and thus indirectly tests the disk system. Jetstress concentrates on the disk system.

You do not have to have Exchange installed to use Jetstress. You can copy a few files to a server and start testing. Jetstress generates a test database, of the size you want. Typically, to get valid results, you only need to generate a database that is 5 percent of the size of your intended production database. You can then instruct Jetstress to make the same changes to the database that happen during normal operation. It adds, deletes, replaces, and reads records from the database. By using System Monitor, you can determine how much actual Exchange load that your disks can handle. You can change your disk configurations and rerun the same tests to see what kind of difference it makes.

We usually recommend that you run Jetstress at least two hours when you are testing to see what kind of sustained throughput your disk system can handle. If you are doing stability testing, the recommendation is 24 hours.

Exchange can subject your server to complex random I/O. As you push computer systems close to their tested limits, and as you run huge amounts of data through the system, you are more likely to encounter glitches or bugs in the ability of the system to reliably process and preserve data. Jetstress will let you load your system until it is running as fast as it can, and will keep it under stress to see if it remains reliable in both storing and retrieving data.

To download the Jetstress tool and other Exchange Server 2003 tools, see Downloads for Exchange Server 2003.

Note that there is a white paper included in the Jetstress package that discusses in detail how to configure Jetstress properly.

Exchange Stress and Performance (ESP) 2003 is a highly scalable stress and performance tool that you can use to stress test Exchange Server 2003. ESP can be used to simulate a large number of client sessions concurrently accessing one or more Exchange Server 2003 servers. ESP includes multiple modules that you can use to simulate a wide variety of protocols and loads.

You can run modules concurrently from multiple hosts, thereby more realistically simulating physically separate client computers. There is no limit to the number of computers on your network that can host ESP modules. Therefore, the load you can apply to your test environment is limited only by the available hardware. Depending on the hardware and workload imposed by each script, it is possible to simulate 5,000 or more end users on a single host computer.

The ESP tool does not have the capability of creating users. Therefore, if you want to create a test that involves simulating actual individual users, and not simply client sessions, we recommend that you use ESP with other tools that create users, for example, Load Simulator 2003.

ESP is modular and extensible. Microsoft currently provides modules that allow you to test the stress that is applied for most Internet protocols. ESP does not include a module to test the stress applied by MAPI clients that use Outlook.

ESP provides modules that simulate client sessions over the following Internet protocols and APIs:

  • HTTP-DAV or Outlook Web Access

  • IMAP4

  • LDAP


  • NNTP

  • POP3

  • SMTP

  • Outlook Mobile Access Synchronization

  • Outlook Mobile Access Browse

ESP 2003 is the tool of choice to simulate users using non-MAPI protocols, also called Internet protocols. ESP 2003 cannot simulate MAPI stress.

ESP 2003 should be used only in laboratories that have no connection to the production environment. This tool should not be used in a production environment or an environment that is mission critical or contains important information anywhere in the network.

To download the ESP 2003 tool and other Exchange Server 2003 tools, see Downloads for Exchange Server 2003.

Note that there is a white paper included in the ESP package that describes in detail how to configure ESP properly.

For more information, see the following Exchange Server blog article:

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