Microsoft falls out of the cloud - again

Another outage has struck a major cloud provider, sending Microsoft's Office 365 and SkyDrive services down for a two-hour period and further knocking confidence in the concept of cloud computing.

Microsoft's Office 356 - a browser-based version of its Office productivity suite, designed to compete with Google Docs and Zoho Office - and SkyDrive - a web-based file storage and backup service - were both knocked out by an unspecified outage at one of the company's North American data centres late last night.

The cause of the outage, which lasted approximately two hours, is not yet known. "At approximately 11:30am PDT, Microsoft became aware of a networking issue affecting customers of some Microsoft services hosted out of one of our North American data centres," explained Microsoft's Steven Gerri in a statement to press. "We worked to isolate the issue and we are beginning to see service restoration. We continue to investigate the root cause of this issue."

The North American outage comes hot on the heels of a failure of the company's Dublin data centre - thought to be caused by an electrical storm which also knocked out Amazon's cloud operation across Europe - which resulted in the Business Productivity Online Suite going offline for the duration.

These recent large-scale outages demonstrate one of the biggest issues with the cloud computing paradigm: while offloading your data centre requirements on someone with far larger economies of scale is tempting, it leaves you helpless in the face of an outage. Worse, a failure at a single data centre can leave thousands of services offline if it's home to a cloud provider, as with the Dublin outage of Amazon's EC2 cloud.

There are certainly advantages to be had with moving to the cloud, but - as companies are starting to discover - it's not without its drawbacks.