It wasn't bad weather, power grid troubles or even a wayward administrator that caused Hotmail, Outlook.com and portions of SkyDrive to fail March 12. According to Microsoft, a data center that houses the IT infrastructure that supplies those services developed a fever.
The trio of cloud services suffered extended downtime—although SkyDrive to a lesser extent—due to a glitch that underscores the importance of proper and uninterrupted cooling in data center environments, particularly those of cloud services providers. While Microsoft did not reveal the exact nature of technical fault, it did involve a firmware update gone awry.
On March 12, Microsoft confirmed reports of the outage on the Live.com service status page. "We're having a problem accessing email. You might not be able to see all your email messages. We're working to restore service right now," reported Microsoft at 5:35 p.m.
As the hours passed, the company supplied frequent, but no less cryptic, updates until the matter was resolved March 13. Now, a clearer picture has emerged.
In a post on Office Blogs, Microsoft Vice President Arthur de Haan explained: "On the afternoon of the 12th, in one physical region of one of our data centers, we performed our regular process of updating the firmware on a core part of our physical plant. This is an update that had been done successfully previously, but failed in this specific instance in an unexpected way."
Like in finance, Microsoft's cloud computing team discovered that past performance does not guarantee future results in IT.
"This failure resulted in a rapid and substantial temperature spike in the data center. This spike was significant enough before it was mitigated that it caused our safeguards to come in to place for a large number of servers in this part of the data center," de Haan wrote.
Those safeguards may have spared the physical infrastructure some damage, but it caused headaches for users who rely on Hotmail and Outlook.com for their email or SkyDrive for their cloud storage. Not only were inboxes and some online file stores rendered inaccessible, failover operations never kicked in.
de Hann's post also provides a clue as to why the outage stretched into the morning hours of March 13.
"Based on the failure scenario, there was a mix of infrastructure software and human intervention that was needed to bring the core infrastructure back online. Requiring this kind of human intervention is not the norm for our services and added significant time to the restoration," he wrote.
Microsoft is keen to restore confidence in its cloud ecosystem. "Now that we're through the resolution, we're also hard at work on ensuring this doesn't happen again," de Hann wrote.
A lot is at stake for the software giant as it makes the transition to a software as a service (SaaS) provider.
On Feb. 18, David Law, Outlook.com director of product management, announced that in the six months since launch, Outlook.com had attracted 60 million active users. And as with most big product releases, Microsoft CEO Steve Ballmer announced the availability of Office 365 Home Premium, a cloud-enabled version of the Office productivity software suite, Jan. 29.