Agents can hurt network performance

Recently we at Enterprise Management Associates deployed management agents to our desktops to facilitate application support over our VPN backbone. The experience has been dicey, to say the least.

While the capability that these agents give our operations personnel to support our virtual workspace is very welcome, the impact these agents have on network performance is not. Although we are working through the tuning of the management technology, the problem we faced illustrates a larger concern that management technology introduces into networked operations: given finite processing, there comes a point where management of a thing affects the operation of that thing.

Of course, readers of this column are familiar with this notion and are probably quite careful about how and where they deploy agents. Plus, it is true that most management suites have focused very diligently on the load their agents place on critical network equipment. However, the fact remains that a poorly tuned agent can consume large amounts of bandwidth, in terms of both network connections and processor cycles.

Even agents with small footprints, or agents that are completely passive until called, can wreak havoc on processors and backbones if the central polling engine is set to ping them at very short intervals. The more data the agent is programmed to deliver, the bigger the impact. Active agents, if poorly tuned, can radically reduce system performance as they attempt to measure and archive every metric in their arsenal.

An increasing reason that this is an issue to watch is that we are now living in an age of clandestine agents. “spyware,” as it is called, has a habit of sneaking into the most highly secured networks and parking itself in the background processes of PCs. Spyware has become such a problem that vendors such as Lavasoft have built a business out of providing filters and scanning applications to find and neutralize these little beasts.

Spyware, along with legitimate agent-based technology, can gobble up resources that would be better applied to the business. Management technology applied without a clear plan or clear objectives can exacerbate the problem.

The lesson, of course, is that management technologies, especially those that park agents in networked devices, must be applied with a particular objective in mind and must be evaluated with an eye towards performance impact. Regardless of whether you are applying management capabilities in conformance to a vendor’s particular recommended architecture or making up a unique architecture comprised of your favorite point products, you need to carefully manage the management technology so that your network is not affected by your attempts to see what is going on.

Additionally, as part of your management arsenal, you need to be aware of all the agents your network may be supporting. The cost of eliminating spyware is very low. Most users will be surprised at how many of the little buggers they are running in the background.

Management agents can provide unparalleled insight into networked infrastructure, but they can also create the very problems that you may be trying to solve. A correctly applied and tuned agent can have a significant and continuing return on investment. You must keep in mind the Heisenberg Uncertainty Principle when using them, however: The more closely you look at something, the more likely you are to change it.