A new study commissioned by VeriSign, provides some interesting findings on the state of DNS availability. VeriSign is a company well-placed to understand DNS, since they operate the .com and .net registries as well as helping to maintain some of the root zone DNS servers for the Internet.
The DNS availability study looked at the availability of the Alexa 1,000 websites during the second quarter of 2011. For those sites that manage their own DNS, the minimum availability was recorded as 95.30 percent. For those that host with a third party managed DNS vendor, minimum availability was reported at 97.14 percent. According to VeriSign that 2.3 percent minimum difference translates into approximately 40 minutes of daily downtime.