There Goes the Neighborhood: Dealing with Noisy Neighbors in Your Infrastructure

By Jim Bahn, Senior Director, Product Marketing

please keep noise to a minimum signEvery neighborhood features the one house that regularly disturbs the peace, whether it’s with loud music, arguing spouses or using the leaf blower at 6 o’clock on a Sunday morning. But did you know that noisy neighbors also exist in data centers and modern infrastructure environments? The generally accepted definition of a noisy neighbor is a co-tenant or application that monopolizes bandwidth, disk I/O, CPU and other networked resources, resulting in a reduction in application performance.

The noisy neighbor issue is ubiquitous, striking Software-as-a-Service and Infrastructure-as-a-Service solutions, as well as legacy data centers. Any host environment that serves more than a hundred virtual machines (VMs) creates a condition ripe for a “rogue” VM to command more than its share of CPU, memory and/or bandwidth, much like how neighbors in an apartment building can cause more disruptive noise than in houses separated by gardens or yards. This misallocation of resources deprives mission-critical apps of the services they need to deliver the required level of performance.

Creative strategies have arisen to help infrastructure managers mitigate the application performance issues created by noisy neighbors, but what if you could identify the troublemakers before the rest of the neighborhood suffered?

Neighborhood Watch

The best way to identify disruptive co-tenants and prevent application performance issues can be likened to establishing a neighborhood watch in your local cul-de-sac. The warning signs that your neighbors are planning a party are hard to ignore—if you know what you’re looking for. It’s easier to ask your neighbor to turn down the music while the night is still young than it is to pick up the beer cans from your lawn and repair the broken windows the next day. Implementing an infrastructure-wide application-centric monitoring tool that analyzes workloads in real time can help find and flag those warning signs, without disrupting the neighborhood’s day-to-day activities.

Context Is Critical

The kind of visibility you need to be able to prevent noisy neighbors in the first place requires a level of real-time monitoring that provides context, not just measurement. For example, a neighbor who has two or three cars in the driveway may not be cause for alarm, but if you add the fact that you live in a duplex with a shared driveway and you know your neighbor lives alone, then those two or three extra cars may be more cause for alarm. The same idea applies to your infrastructure. By not only monitoring the performance of your applications but also providing context into how and where they’re being used, you can ensure that the warning signs are, in fact, warning signs.

Intervention Time

So, the cars in your neighbor’s driveway are starting to clog the street, the music is getting louder and voices are getting rowdier. It’s time to intervene, but you don’t necessarily want to get the police involved. Because you’ve kept close tabs on the activities leading up to the party, you can take preventative action before the problem becomes too big to handle. Consider offering additional driveway parking for the cars parked in the street (reallocating bandwidth to more important services), asking your neighbors politely to turn the music down (scaling back non-mission-critical applications), and/or helping the neighbors break up any loud arguments (shutting down power-hungry services temporarily to ensure the performance levels of other applications).

Don’t Get Lazy

You’ve successfully managed to get through the night without a 911 call or barrage of car alarms, but the work isn’t over yet. Just as you wouldn’t disband the neighborhood watch after a burglary is resolved, don’t stop monitoring your infrastructure after you address a performance issue—even if it was only a potential performance issue. As IT environments continue to increase in complexity and “neighborhoods” become more crowded, the noisy neighbor issue is only likely to worsen.

However, by remaining vigilant and continually monitoring for resource-hungry applications, you can detect and remove noisy neighbor problems now and ensure that your organization’s mission-critical applications will remain undisrupted. After all, a peaceful neighborhood makes for happier – and hopefully quieter – neighbors.

To learn more about noisy neighbors, check out my article in Data Center Journal.