If you want to gather LoadSim-specific performance information, you need to install the LoadSim counters on the clients. To install the counters, open a command prompt in the LoadSim folder and type
unlodctr loadsim
This command removes any previous versions of the counters. Next, to enter the necessary registry information, type
lsperf.reg
Accept the prompt to enter the information in the registry. To load the new counters, type
lodctr lsperf.ini
Copy or move the lsperf.dll file to the \%systemroot% directory (usually \winnt). Finally, launch Performance Monitor (you can do so from the command prompt) and verify the presence of the LoadSim Global and LoadSim Action Performance Monitor objects.
Defining the Test
After you configure the clients, the next step is to define the Exchange environment. Define the storage groups (SGs) and mailbox stores on each Exchange server you want to test. Make sure that the SGs and stores match your production Exchange configuration, especially if you place log files and databases (i.e., .edb and .stm files) on separate physical disk arrays. Open each SG's Properties dialog box, go to the General tab, and select the Enable circular logging check box. This action might run against everything you've ever been taught, but if you don't enable circular logging, the transaction log volumes will fill up during the mailbox initialization process. Don't worry—you'll turn off circular logging before you run the test load. When you see the prompt that Figure 2 shows, click Yes to continue.
Launch LoadSim on one of the clients. From the LoadSim menu bar, select Configuration, Topology Properties to open the Topology Properties screen, which Figure 3 shows. (Earlier LoadSim versions' screens are quite different: You need to add the servers to your test configuration and specify the server location properties—i.e., Admin Group, Organization, and Internet Address—manually.) On the Servers tab, expand each server object to see the SGs and mailbox stores that you configured earlier. In the right-hand pane, enter the desired number of users for each mailbox store. This step is tricky at first because you must expand the SGs, then click and edit in the right-hand pane the number that corresponds to each mailbox store. You can enter numbers only for the mailbox stores; LoadSim then calculates and displays the total number of users for each SG and server. You can distribute users however you want; you define the actual running load for each client later. For example, you can specify 500 users per mailbox store, then initialize and run only 400 of those users.
On the Topology Properties screen's Security tab, you can choose the Use a separate account for each user or Use one account for all users option. I prefer to use a separate account for each user because that option more accurately reflects logon activity on your domain controllers (DCs). On the Topology Properties screen's Distribution Lists tab, you can define the number and depth of DLs; I find the defaults acceptable.
The next step is to specify the number of users per client test machine. From LoadSim's menu bar, select Configuration, Test Properties to open the Test Properties dialog box, which Figure 4 shows. (When you first open this dialog box, the User Count column in the User groups section will contain only zeros.) In the Duration of simulation section, you can specify the length of your test run; an official run needs to be 8 hours. You can run a shorter test, but keep in mind that the test includes a warm-up period during which LoadSim logs on users; Exchange responds to the increasing load by allocating memory to the Store process through Dynamic Buffer Allocation (DBA). Don't analyze any information until Exchange reaches a steady-state period—usually after 2 hours. You can also specify daytime and nighttime periods to differentiate full-load from partial-load periods when you leave LoadSim running for more than 24 hours—which is useful for testing a WAN before placing users on it.
To add a user group, click Add in the User groups section. This action opens the Edit User Group dialog box, which Figure 5 shows. First, select the server that you want to run the load against. When you select a server from the Server drop-down list, LoadSim automatically limits subsequent input to the total number of users that you specified for that server. Although you entered those users according to mailbox store, the Edit User Group dialog box doesn't let you specify which store the users are homed in. Instead, you enter the server, the number of users, and the client that will generate the load. For the most part, accept Outlook in the Protocol box and MMB2 in the User type box. Enter a number in the First user box, then enter the Number of users you want in this group. Keep in mind that LoadSim considers 0 to be the first possible number (e.g., if you enter 0 as your first user and specify 250 users, the Users covered will be 0-249). In the Client Machine box, specify the client machine that will run the load, keeping in mind the constraints of 200 to 500 simulated users per client. Click OK to return to the Test Properties dialog box. Repeat the process to add more groups, spreading users over all servers and available client machines. Click OK to close the Test Properties dialog box.
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