A long time ago, in a galaxy far, far away, a moisture farmer from Tatooine was able to blow up a planet-destroying Death Star with a single shot down a narrow pipe (well, and with the Force). You would have thought that the Empire would have bolstered protection for the reactor in its replacement Death Star, but no -- entire ships were able to fly right to the core to blow it up too (once the shield generator was taken out).
The mega-clouds that are increasingly replacing data centers may also have such fatal flaws that could blow them up.
Take Office 365. Time has proven that it's not infallible. There have been several major outages in the past two years, as well as many minor outages. The causes have varied, so there's been no common fatal flaw discovered thus far.
For example, a December 3 outage in Europe had nothing to do with Office 365 itself but caused five hours of turmoil of customers, affecting, according to news reports, 1 percent of Outlook users on the desktop and 35 percent of Outlook users on the Web. And users were also unable to get into SharePoint, Power BI, Intune, and Yammer.
The issue occurred in Azure Active Directory: A configuration error caused authentication failures for Web protocols. We now know that Office 365's dependency on Azure is one of the weak spots in the service.
IT admins can easily see and understand the connection between server applications and Active Directory. For example, on-premises Exchange requires Active Directory to authenticate users and protocols. So if you're having issues with DNS, connectivity, or any number of other things, your messaging environment will not work if it cannot communicate with Active Directory.
As Exchange MVP Tony Redmond has detailed, Exchange Online has a similar dependency on Azure Active Directory for authentication -- and thus the same weakness.
Microsoft, while not apologetic about the outages, said it plans to make a variety of improvements to the service -- mainly improved testing and fallback options -- as well as better communication to users of service status.
While you wait for Microsoft -- or any mega-cloud provider -- to make the perfect, indestructible cloud with amazingly transparent communication to its users, you can adopt third-party continuity offerings (like Mimecast) and monitoring offerings (like ENow's Mailscape).
Do your research and find the ones that are right for you. And may the Force be with you.