Is your ‘cloud’ delivering the expected performance?

Cloud services are all the rage now and becoming increasingly so, but how do you actually measure performance? Daryl Cornelius*, Director Enterprise EMEA, Spirent Communications, asks: How do you know until you test it? What are the complexities of measuring virtual systems?

As you sit at your PC cursing the little window saying your software needs updating (and asking whether you would rather waste time doing it now, or waste time later) the idea of software delivered to your computer from a pure source, like mains water or electricity, becomes highly attractive.

It’s basically not a new idea, because it harks back to the old days of a central mainframe doing all the processing while users interact via a network of dumb terminals. It re-emerged in the early 90s with talk of the ‘thin client’ and then with internet intoxication came the idea of software as a service - buying usage only as needed from a source that managed all the licencing and upgrading and kept the applications in peak condition.

The main difference is that a new name was needed to mark the fact that this idea now works. Pioneering attempts failed simply because broadband access was not yet, widely, good enough to support the service, but with today’s widespread broadband it is becoming a practical proposition. It’s called cloud computing because, instead of the processing happening inside your computer or in the company mainframe, it happens at some unknown location in the internet cloud.

As before, the key to successful service is that the network to the mobile or desktop computer must be fast enough not to frustrate a user who is used to the speed and responsiveness of onboard software. Also, in the case of software running in a virtual server, the network connecting its parts must be sufficiently fast and low latency to allow the application to perform as well as it would on a single physical machine.

Performance really is the challenge. Cloud computing potentially offers all the benefits of a centralised service - pay for what you actually use, professional maintenance of all software, single contact and contract for any number of applications and processing on state-of-the-art hardware.

So how does the provider ensure that level of service? The answer must lie in exhaustive testing. The complexity of virtual systems makes for unpredictable behaviour; you can only be sure when you have put it to the test. But there is also a fundamental problem in testing any virtual system.

Seen in those terms, there has been no absolute, definitive way to put virtual systems to the test. Spirent has, however, come up with a virtual test solution. Every change must be tested to avoid mission-critical business applications from grinding to a halt.

There are two aspects to testing applications in a virtual environment. Firstly functional testing, to make sure the installed application works and delivers the service it was designed to provide, and then volume testing under load.

Load testing is an altogether different matter in a virtual system and, even more so in the cloud, there can be unusual surges of traffic leading to unexpected consequences.

Cloud computing offers many advantages to the user, but the provider must assure the client that the service will consistently deliver on its promises. Fail, and users will vote with their feet. The only way to ensure success is to offer a tried and tested service. Spirent has the necessary solutions to ensure that, along with a revolutionary approach to testing a virtual environment, Spirent Virtual can generate a virtual test structure in the cloud itself.

*Daryl Cornelius is the Director of Enterprise, EMEA at Spirent Communications. For the past four years Cornelius has been growing business in the enterprise, government and military markets, through tailored professional services and solutions specialising in network and web applications, load, stress and security testing.