Understanding and Using LoadSim 5.0: Part 2

Last month, in the first part of this series, I explained what LoadSim is and what you can use it for. This month, I will walk you through an example scenario, explaining installation and configuration. In the remaining articles of this four-part series, I'll use this example to show you how to install, configure, and customize LoadSim and how to collect and analyze data.

Using LoadSim
In my example, Microsoft Exchange Server is up and running. But before I deploy it and put real users on it, I want to see how the server holds up against the required user load.

For my test scenario, I assumed two major requirements. First, I wanted to ensure that one server sufficiently handles 300 users that closely match LoadSim's Medium user profile. You definitely want performance to be great, and you want to make sure the server doesn't fall over and die when you turn users loose on it. Second, I wanted response times of 1 second or less. This value is standard, and users generally don't get impatient if response time stays in this range.

My example considers the simplest case, in which you have only one server in the Exchange organization. You can test multiple servers with LoadSim, but I focus on the single-server scenario because it covers the majority of the concepts and parameters you need to know about. When you understand those concepts and parameters, you can then configure LoadSim to do a multiple-server test.

Collecting the User Profile Parameters
Last month, I introduced the user profile parameters: Light, Medium, and Heavy. Table 1, page 162, shows the required parameters for a Medium user, the target for my example. The table shows all the parameters you can customize in LoadSim, so if you want to change some of them for your specific requirements, you'll know what to look for. When you've collected the required data for your test user profile, you can install and configure LoadSim.

Notice that I didn't specify any public folder activity in the profile. LoadSim can simulate public folder tasks, but the focus in this example is configuring for email tasks, which are private folder tasks. Fortunately, configuring for public folders is similar and uses similar principles. Along the way I mention specific public folder options so that they won't be unfamiliar to you.

Installing LoadSim
The installation process has two parts and is easy to do. First, you must install the Microsoft Exchange Client software for NT. This step is crucial because LoadSim cannot talk to Microsoft Exchange Server on its own. It must have the client software. Outlook can also serve as the client software, but LoadSim is not simulating an Outlook client. It is simulating an Exchange client. The Outlook software merely serves as the mechanism for LoadSim to talk to Exchange Server.

Next, you install the LoadSim software. LoadSim has no setup program. You simply copy the files to a directory on the LoadSim client's hard disk. (As I mentioned last month, LoadSim is not on the Exchange Server 5.0 CD-ROM. By the time you read this article, you should be able to download a version of LoadSim with full Messaging API­MAPI­support from Microsoft's Web site; this version is equivalent to the LoadSim shipped with Exchange Server 4.0.) Copy the files to a directory such as \LOADSIM on your LoadSim client's hard disk. For convenience, you can make a shortcut for LoadSim in a location of your choice in NT. I usually put the shortcut in the same group as the other Exchange client stuff.

Configuring LoadSim
LoadSim configuration consists of five main steps: configuring the LoadSim test topology properties, configuring distribution lists, configuring LoadSim test properties, creating the LoadSim test topology and importing users into Exchange, and setting LoadSim options. To configure LoadSim, you generally follow the Configuration, Run, and Tools menus in order. Some of the menus have a lot of information, but if you work through them in that order, you won't go wrong. Let's look at each of these five steps.

Step 1: Configuring LoadSim Test Topology Properties
First you configure the topology properties. Topology is a fancy name for specifying the test infrastructure, such as the name of the server under test, public folder configuration, quantity of clients and client protocols, and distribution lists. The topology properties form the basis for the remainder of the test configuration.

From the Configuration menu, select Topology Properties. Screen 1 shows the resulting properties sheet, which is blank the first time you open it. You must add the relevant information about the server to be tested. Click the Add button to bring up the Server Properties sheet with the Type tab displayed. You must enter the information in the Server name, Site, and Organization text boxes exactly as you configured Microsoft Exchange Server, as I did in Screen 2. LoadSim fills in the Internet address text box for you as you type.

If you are setting up for public folder tasks, you need to click the Custom Properties button on the Type tab and enter information in the dialog box. Tell LoadSim how many root folders and nonroot folders you want, how deep you want the folder tree to be, and how many messages you want in each folder. LoadSim will use this information when it seeds the public store with folders when you run Public Folder Initialization.

After you complete the Type tab, you can open the Users tab, which provides a place to configure the number of LoadSim users in the topology. Note that the number of users you specify is not necessarily the number of users this machine will simulate. In this property sheet, you are configuring the properties of the topology for the entire test, not just for this machine. You'll get to configure the number of users for this particular machine shortly. I configured my test to use 300 clients with the Exchange (MAPI) protocol.

After you specify the number of users, click OK to return to the Topology Properties dialog box. Screen 3, page 164, shows the entry you just made. It shows the name of the server, the number of users, the site, and the organization. This information becomes important later, because the number of users you enter here dictates the number of users available when you are configuring the test.

Let me give you a brief description of the Security tab. In this version of LoadSim, Microsoft added the ability to configure which NT user account the LoadSim user will utilize when the user logs on. The default is to use a separate account for each user, because in the real world, each user has an NT user account. Sometimes, using one NT account for all LoadSim users will be convenient, especially in huge test runs, so that you don't have to configure a bunch of NT accounts. I recommend using the default to keep things as realistic as possible.

Step 2: Configuring Distribution Lists
Using distribution lists (DLs) is an optional part of any LoadSim test. But because the example user profile says the user adds a DL to the address list 30 percent of the time, you need to be sure to enable use of DLs. You don't configure the 30 percent usage here; you can just turn DLs on or off and configure their sizes.

In the Topology Properties dialog box, select the Distribution Lists tab. The default is for DLs to be enabled, so leave the Use distribution lists check box selected. You'll also find some customization parameters for DLs here.

The DLs per site entry configures how many distribution lists LoadSim will have in the site. Here, the default is 30. A given recipient can be in one or more DLs.

The last three entries—Minimum DL size, Average DL size, and Maximum DL size—configure how many users are on each DL. You can specify whatever you want, as long as the number doesn't exceed the total number of users you have. I used the default, 10, for the average number of recipients on the DL. Changing this number affects the calculated number of emails sent and received in a day. Click OK to close the Topology Properties sheet and move to the next step.

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