There is a reason why Amazon Inc. has been able to maintain a stronghold over the public cloud for the better part of the past decade. In addition to boasting the broadest selection of capabilities and lowest prices of any major provider, Jeff Bezos’ firm apparently also offers the best service availability rates, according to the latest annual uptime data from CloudHarmony.com.

The vendor comparison site’s aggregate figures for 2015 show that Amazon’s platform suffered just two and half hours of downtime, slightly better than its total tally in the previous year. Since CloudHarmony only tracks infrastructure services, the number doesn’t include the several-hour blackout that many users of the company’s managed DynamoDB database experienced in September, which gave it a comfortable lead over key competitors.

Microsoft Corp. witnessed 71 individual outages across the core compute, storage and content delivery functions of its rivaling Azure platform in 2015 that contributed to nearly 11 hours of downtime, while Google Inc. emerged closely behind with 76 incidents totaling some 11 hours and 34 minutes. The next two spots on CloudHarmony’s list went to hosting industry veteran Rackspace Inc. and developer darling DigitalOcean Inc., which each saw about 12 and a half hours worth of service disruptions last year.

The company that fared the worst among the bigger names on the tracking site’s list was IBM Corp., which racked up more than 17 hours of downtime over the past 12 months. The data adds insult to the injury of its cloud platform’s recent designation as the world’s top source of spam in 2015, a situation that Armonk will no doubt try to remedy before next year’s results come in. As the stakes continue to grow higher in the public cloud, so will the importance of service reliability to the value propositions of the top providers.

Photo via hongmyeon