The cost of cloud downtime

Cloud computing promises dramatic savings -- but only if downtime is kept in check

Twitter makes you think. Last week, hundreds of tweets were flying when a cloud host had connectivity issues with one of its datacenters. I know intermittent IT infrastructure issues are nothing new, but I started wondering: What happens when something fails and you don't own the infrastructure?

Thanks to Twitter, I got to watch the journey from frustration to satisfaction firsthand. Around 3:50 p.m., the host's engineers started working on the issue, and to their credit, they posted regular status updates to an external blog for their customers right up until 4:25, when service was restored. So what started as a minor service outage lasted approximately 35 minutes. That's 35 minutes of downtime for a customer. If I were a customer, I'd think 35 seconds of downtime was an issue.

And it wasn't just one customer. Even if there were only 100 customers on this infrastructure, that's roughly 58 hours of aggregate downtime. 58 hours! What if those 100 customers hosted their entire business on the cloud?

[ Downtime issues will become even more important as cloud computing is looking like the big trend for 2009. ]

Is this cloud computing's limiting factor? Maybe. And maybe selecting your business's IT infrastructure is like investing for your retirement: You never want to put all your eggs in one basket. Some small businesses are doing just that to get off the ground.

This type of outage is fairly common -- we've all been there. But the very next day, those same engineers were alerted of another outage at 12:55 p.m. that they were still troubleshooting at 1:30 p.m. and that was still affecting customers intermittently at 5:16 p.m. That's more than 70 minutes in 48 hours. Let's be generous and say an hour. How much would an hour of downtime cost your business?

Last week I told you that Ynema Mangum and George Reese agree that deploying within the cloud saves an average of 29 percent over an internal IT department. So here's the question: At what point would the cost of downtime eclipse the savings?

I know you relish leaving me comments -- it's what I love about InfoWorld. This time, do some simple math for me before you pick this post apart, will ya? How many hours would your cloud host have to be down before the cost eclipsed 29 percent of your annual IT budget? Lead your comment with your answer, then pontificate away.