Amazon offers uptimes guarantees for online storage

Computerworld - Amazon this week unveiled a new service level agreement  (SLA) that it said guarantees that customers using its hosted Simple Storage Service (S3) will receive at least 99.9% uptime each month.

If the S3 service fails to meet that level of service, Amazon will provide service credits to qualified users, said Adam Selipsky, vice-president of product management and developer relations for Web Services. 

The new SLA for the online hosted storage service went into effect on Oct. 1, the company said.

Selipsky said the service credits will be distributed in cases of internal server errors or a "denied request." A server error occurs if an end-user pings S3 and receives "InternalError" or "ServiceUnavailable" replies, he said.

Based on the S3 SLA, the exact number of those error messages received will be divided by the total number of requests during each 5-minute period, said Selipsky. Amazon will then calculate the error rate for each Amazon S3 account as a percentage of each 5-minute window within a monthly billing cycle. 

Service credits will be calculated based on a percentage of total charges paid by an S3 user for the online storage service within the billing cycle in which an error rate occurred, Sllipsky said.

The new program is not accompanied by an upgrade to the hosted service, he noted. "There's a decent number of customers who asked us about this over time. Ultimately, you are judged on your track record and not promises you make," he said.

Doug Chandler, research director for Infrastructure Services at Framingham, Mass.-based IDC, said online storage services vendors have little choice but to offer bullet-proof SLAs and other guarantees to storage buyers.

"Storage buyers, in my opinion, are among the most conservative buyers in the IT world and are unlikely to move to a new model without some pretty serious assurances that have some teeth to them," said Chandler. 

He continued, "To be taken seriously, Amazon and all their competitors are going to have to do this because those customers in this model are funneling their business on that storage."

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