Microsoft’s Azure cloud service suffered a worldwide outage that started Tuesday and was apparently triggered by a timing miscalculation for the leap year. The company was continuing to work on Wednesday to resolve the Azure outage, which continued to affect some customers.
Microsoft said it became aware of an issue impacting the service management component of Azure at 5:45 p.m. Pacific Time on Tuesday.
“The issue was quickly triaged and it was determined to be caused by a software bug. While final root cause analysis is in progress, this issue appears to be due to a time calculation that was incorrect for the leap year,” Bill Laing, leader of the Azure engineering team, wrote in a blog post.
Microsoft created a fix and deployed it to most of the Windows Azure sub-regions, which restored the Azure service to most customers by 2:57 a.m. PST on Wednesday, he said.
“However, some sub-regions and customers are still experiencing issues, and as a result of these issues they may be experiencing a loss of application functionality. We are actively working to address these remaining issues,” he said.
In an email statement, a Microsoft spokesperson said some customers in three sub-regions – north central U.S., south central U.S. and North Europe – remained affected late Wednesday afternoon. Customers might have issues with Access Control 2.0, Marketplace, Service Bus and the Access Control & Caching Portal, which could result in loss of application functionality, the spokesperson said.
Windows Azure Storage was not impacted, according to Microsoft.
UPDATE: Microsoft reported Thursday at 10:13 a.m. Pacific Time that the Azure service disruption was completely resolved.