Enterprise Testing Environment

The Windows NT Magazine Lab can model a variety of networkarrangements to test the performance of enterprise-class server hardware andsoftware. This capability presents several requirements that our hardware andsetup must satisfy.

For example, Internet testing requires simulating transactions from theoutside world, which necessitates IP addresses other than our own. Messagingwith Microsoft Exchange requires a domain model, so we set up a domaincontroller. This system now also functions as a WINS server. The simulatedclients must participate in this domain, and the high loads we generate requirethat we spread out client loads across multiple logical--and physical--networksto prevent network I/O bottlenecks.

You can test Microsoft SQL Server (or any database) either in a domain or aworkgroup--in a 1000+ user environment, you're more likely to find a domain thana workgroup. The Lab uses Bluecurve's Dynameasure for end-to-end capacity andperformance testing. Optimal arrangement of the testing hardware means separatesystems for the control server (which manages test operations and stores resultsdata), the management console (for administering tests), and the test server(the system under load)--all of which need high-speed I/O pipes to the rest ofthe client/server environment.

When we moved from 15 to 35 client workstations simulating user load, wedecided to spread these thousands of virtual users among several networks tomore closely simulate the real world and to remove network I/O as a potentialperformance trap that would affect test results.

This move required additional networking hardware and another high-powerserver. As you can see in Figure 1, we set up four VLANs: one for the resourcesystems and three for the clients. One server acts as the DHCP and MPR system;the Cisco switch keeps the VLANs physically separated, while still offering thebest possible performance; and the added hubs give us extensibility. Thisfunctional network is reasonably easy to administer.