Microsoft has admitted a dodgy firmware upgrade cooked its servers and knocked its Hotmail and Outlook.com email services offline for 16 hours.
In a postmortem examination of the disaster, the Windows 8 giant said a software upgrade for its data centre equipment - an update that had worked successfully in the past - failed unexpectedly on the afternoon of Tuesday, 12 March. The cock-up resulted in a “rapid and substantial temperature spike” in the hall housing the websites' servers.
Microsoft did not say in which of its many data centres the machines are based. The company's online storage service Skydrive was also affected but brought back online faster than its web siblings.
The Hotmail and Outlook.com rack-mounted computers weren't the only systems getting hot under the collar: irate users vented on Twitter their displeasure at being unable to access their emails for nearly a full day.
Microsoft veep Arthur de Haan said the soaring mercury triggered unspecified “safeguards” in the data centre that shut down the sweating servers before the fault turned really nasty - albeit without switching to the backup:
These safeguards prevented access to mailboxes housed on these servers and also prevented any other pieces of our infrastructure to automatically failover and allow continued access. This area of the datacenter houses parts of the Hotmail.com, Outlook.com, and SkyDrive infrastructure, and so some people trying to access those services were impacted.
De Haan’s analysis continued in torturously overworked prose to explain that, in non-technical terms, some techies tried turning it off and back on again to fix it. The exec himself put it thus: “There was a mix of infrastructure software and human intervention that was needed to bring the core infrastructure back online."
His explanation was infused with standard-issue corporate-grade apologies and attempts to play down the impact of the outage. De Haan said the vast majority of Hotmail, Outlook.com and Skydrive users weren’t affected, adding that Microsoft “sincerely apologises" and takes any downtime “very seriously”.
The problem hit Hotmail accounts being migrated to Outlook.com and is the second such failure in less than two months. Microsoft’s goal is to transfer all 360 million Hotmail inboxes by the summer. Hotmail is still the world's largest free email service.
The fact that a regular firmware update had near-disastrous consequences should raise a few eyebrows: after all, cloud-based services are, by design, supposed to keep ticking even if they take a kicking without outsiders noticing. ®