Today we'll take a deeper look at trends and issues in web reliability and uptime, prompted by the front page coverage in The New York Times story. Yesterday we asked whether downtime is more frequent or just more noticeable, and itemized some of the major outages that have made headlines over the past year. There have been some whoppers, suggesting to some that "five nines" is a pipe dream.
Looking at outages, however, presents just half the picture. How many companies are providing exceptional uptime? For a broader analysis of trends in web site availability, we took a look at Netcraft's public reliability ratings of web hosting companies. In June, 37 of the 48 providers (77 percent) tracked by Netcraft had perfect uptime, while 35 out of 47 (74 percent) had no downtime in May.
It should be noted that the rankings are based on the availability of the hosting providers' main page, which doesn't always reflect user experience. As a result, The Planet has just 17 minutes of downtime for June, even though some of its users were offline for days in early June due to an explosion and fire at one of the company's Houston data centers.
There's also significant variation in performance. Datasnyc, for example, was one of the best performers in June but had the longest single outage in May.
If three quarters of hosting providers are delivering perfect uptime, is the glass one-quarter empty or three-quarters full?