When choosing a webhost, one of the most important factors to think about is their history of downtime. The unfortunate truth is that all webhosts will have some downtime, even if it’s only minutes a year. But maintenance and other reasonable issues with data centers can cause your website to be inaccessible for some time.
So what is a realistic expectation of downtime you might have with a hosting provider? According to a recent survey of 67 data centers, unplanned total data center outages lasted an average of 86 minutes in 2013, while partial data center outages lasted 56 minutes. The same survey found that one minute of downtime can cost customers an average of $7,900 in potential sales, client damages, and other unforeseen complications. Update: in 2016, the average cost of a single minute of downtime is $8,851, almost $1000 more than one a few years earlier.
In the webhosting industry, uptime is measured by nines: a webhost can have anywhere from 99% to 99.999% uptime. In your service-level agreement, or the contract you make with your webhost, the webhost will promise a specific amount of guaranteed uptime. A webhost that promises 5 nines, or 99.999% uptime, has about 5 minutes of downtime each year, a level of leeway usually reserved for maintenance. However, 99% uptime amounts to a little less than 4 days a year of downtime.
Given that the average downtime for data centers in 2013 was between 56 and 86 minutes per incident, a realistic expectation of downtime for your host would be about 99.99% uptime. The industry standard for data center uptime is 99.9%, or a little over 8 hours of downtime each year – meaning that if your webhost has been down more than 8 hours in one year, they are below industry standards.
Hosting providers that don’t live up to their promises in your service-level agreement or are below industry standards can cost you thousands of dollars. In a recent incident where BlueHost was down for about 24 hours, customers flocked to Twitter, many of which complained that they had lost some of their clients due to the inaccessibility of their website.
— James Timothy White (@officialjtw) April 17, 2014
Before hosting a website anywhere, compare their promise of uptime with past customer complaints. If lots of customers have recently voiced grievances online about the webhost’s downtime, you should avoid that hosting provider. If customers are routinely satisfied with the accessibility of their websites, you know that webhost lives up to its promises.
“One Minute of Data Center Downtime Costs US$7,900 on Average.” http://www.datacenterdynamics.com/focus/archive/2013/12/one-minute-data-center-downtime-costs-us7900-average. (22 April 2014).
Turner, Sam. “How much website downtime is acceptable?” http://blog.iweb.com/en/2012/11/how-much-downtime-is-acceptable/11469.html. (22 April 2014).
Leggatt, Helen. “45% of major U.S. retailers have uptime below industry standard.” http://www.bizreport.com/2012/11/45-of-major-us-retailers-have-uptime-below-industry-standard.html. (22 April 2014).
Updated information from “Average Cost of a Data Center Outage” http://datacenterfrontier.com/average-cost-of-a-data-center-outage/ (17 June 2017)