After the production environment has been mimicked on Virtual Enterprise, user activity is simulated through scripted transactions. The testers may establish preferred service levels, such as completing successful user logons within seven seconds, then generate user traffic until that limit is reached or broken, telling the testers something they wouldn't be happy to discover in production systems, says Amichai Lesser, product marketing director.
One drawback of simulated environments is that applications run on a network that looks little like the network within the production environment. "Trying to re-create the network is more difficult. It never comes close to the real network" with its geographically scattered devices and user traffic streaming in from many locations, Lesser says.
But the advantage lies in repeating a problem under simulated conditions where it can be closely monitored, he says. Intensive monitoring in a production environment disrupts the application and can skew results. In a simulated environment, an application problem can be repeated under different conditions until a solution is found.
Every production environment has memory leaks and other problems that are hard to duplicate in a laboratory or troubleshooting environment, Metzger says. They show up best where you don't want them, in the applications being seen by users.
That's why Nix at the University of Kansas Hospital believes his application diagnostic tools are worth what he's spending on them. The $15,000 he saved with Siemens, he says, paid for half the cost of nGenius "in one event."
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