Cloud Computing, Part 3: SLA Spirit in the SkyThe KISS MandateAll Over the MapBeyond 99.99 PercentA New SpaceCloud Computing, Part 3: SLA Spirit in the SkyBy Erika MorphyTechNewsWorld 11/13/08 4:00 AM PT "Cloud computing" is an apt name for a technology that is many things to many people. Although each vendor that enters the space seems to have a different approach to cloud services, all of them face a common challenge: coming up with an achievable service guarantee to reassure hesitant customers.Google arguably is the granddaddy of cloud computing, at least in its current incarnation. So, whenever the Googleplex develops a new feature or capability -- or service offering -- the rest of the industry takes notice. That was the case last month when Google rolled out a service level agreement (SLA) that guarantees 99.9 percent system accessibility for users of its Google Apps Premier Edition -- a cloud-based suite that includes business-oriented messaging and collaboration apps, along with support and integration capabilities.Google had already been offering an SLA for its premium service Gmail; its new announcement was an extension of that agreement to cover Google Calendar, Google Talk, Google Docs and Google Sites as well.Essentially, the SLA promises that services will be operational at least 99.9 percent of the time during any calendar month. If there's an outage, affected customers will receive service credits. Google defines "downtime" as a period in which there is a more than a 5 percent user error rate as measured by server side error rate lasting 10 consecutive minutes. Intermittent downtime for a period of less than 10 minutes does not count.The demand for an SLA is understandable, especially in a new category of computing, said Matt Glotzbach,product management director for Google Enterprise. They can be a security blanket for users new to the cloud. "A business adopting cloud computing is making a big transition moving from a system that's under their direct control," Glotzbach told the E-Commerce Times. "It is an emotional as well as operational change, because previously you could touch the servers you were managing." The KISS Mandate Still, Google is keeping its SLAs as pared down as possible by establishing simple definitions for service reliability, Glotzbach said -- adding that he hopes the rest of the industry will do the same. "The customer wants to know if it can access services -- not whether the vendor has met the defined throughput or latency figures," he said. "Businesses do not care about those metrics. If there is a breakdown and the customer couldn't access a system for hours with no explanation, do you think he would be satisfied with the response by the vendor that 'well, I did meet latency as we agreed'?"Indeed, this is the crux of an argument typically made against SLAs: Businesses and their risk managers may love the assurances they offer, but these documents can also be a dodge for vendors that fail to meet the spirit of their promises. As cloud computing gains more momentum, both users and vendors will be watching closely to see whether providers' uptime promises are geared more toward the spirit or the letter of the agreement. All Over the Map Right now, SLAs for cloud computing are all over the map, Gerry Libertelli, president and CEO of ReadyTechs, a digital infrastructure services firm, told the E-Commerce Times. "I have seen companies saythey have no SLA -- and I have seen a companies go completely overboard."Part of the problem is that in the case of cloud computing, SLAs can be particularly difficult to pin down; the very nature of the cloud is redundancy. "Technically, there should be zero downtime associated with a cloud instance, since almost everything in a cloud -- CPU, RAM, disk -- is redundant by nature and easily reinstantiated in the case of a failure," Libertelli pointed out.There are contingencies specific to cloud computing that must be taken into account, Libertelli continued. "For example, many Cloud vendors tout zero downtime for cloud configuration changes. This is impossible, since almost all the hypervisors we know of require you to bring a cloud instance down, make the configuration change, and then launch it again. That is not exactly zero down time, and it really begs the idea of redefining the standard network services SLA to include cloud-specific contingencies."In other words, he explained, there's a big difference between terms like "average configuration downtime" and "network downtime" as opposed to "systems downtime." ReadyTechs' SLA centers on how fast the company will acknowledge a problem and then how fast it will bring resources to bear on an identified issue. This is the most effective way to deal with issues that concernthemselves with an SLA, Libertelli said. This is not to be confused with bandwidth SLAs, of course, which can be measured using the 95th percentile and are much easier to assess. Beyond 99.99 Percent Perhaps because performance and availability differ with cloud computing, some vendors are taking a moreexpansive approach with the promises they make."The key insight is that in cloud computing, the accountability for operating the system shifts from the customer's IT department to the vendor," Intacct SVP Dan Druker told the E-Commerce Times. "Mature cloud vendors like Intacct have figured out that service level agreements should guarantee the performance of items that are no longer under the IT department's control."Its SLA includes commitments around system availability, disaster recovery, customer support response time, problem resolution, implementation quality, billing accuracy and roadmap communications."We also explicitly guarantee that our clients own their own data, and that if they ever decide to leave us, we will help them to get their data out of our systems," added Druker. "The system just has to work -- and that means much more than a single aspect of operations like availability or support. So it's very important that buyers of cloud computing solutions really think hard about how the entire system is going to work, and make sure that they are comfortable with the guarantees their vendor is willing to make for them."Another factor is that companies themselves are becoming far more sophisticated in terms of expectations and demands. For instance, most clients of Xignite, a financial Web services provider that delivers market data from the cloud, are fine with the 99.5
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