Ubuntu founder Mark Shuttleworth wrote a blog post today pointing out that the popular Linux distribution has seen an increase in enterprise server adoption over the past year. He published a graph which indicates that Ubuntu deployments have surpassed those of Red Hat Enterprise Linux (RHEL) among the top one million most popular websites.

This is a noteworthy milestone for Ubuntu because it reinforces the distribution's relevance beyond the desktop. The strong pattern of growth illustrates that Ubuntu is a serious contender in the server market. It's important to remember, however, that Ubuntu server deployments don't all equal paying customers for Canonical. Ubuntu still has a long way to go before it will match RHEL's commercial success.

Unlike RHEL, which is typically coupled with a commercial service agreement, Ubuntu receives updates at no cost. Only a small portion of Ubuntu adopters pay Canonical for support and management tools. Users who want Red Hat's product at no cost typically adopt a popular RHEL derivative called CentOS. Deployments of CentOS still significantly outnumber those of Ubuntu.

The data comes from W3Techs, which analyzes the top one million websites and catalogs the technologies they use. According to data from W3Techs, Ubuntu is now the third most popular Linux distribution on servers. Their data shows that the most popular Linux distribution is Debian, the free community-driven distribution from which Ubuntu was derived.

Debian hosts 9.8 percent of the top one million websites. CentOS is a very close second place with 9.5 percent. Ubuntu comes in third with 6.1 percent. RHEL follows in fourth place with 4 percent. Just for fun, we checked the stats on Fedora, which has 1.6 percent, and Gentoo, which has 0.4 percent. Ubuntu climbed up from 4 percent last year while RHEL declined from just under 5 percent.

Shuttleworth attributes Ubuntu's rapid growth on servers over the past year to a renewed emphasis on quality across the aboard. He also said that another major factor is Canonical's strong focus on delivering good support for deploying Ubuntu in cloud environments, such as OpenStack and Amazon's EC2.

"The key driver of this has been that we added quality as a top-level goal across the teams that build Ubuntu-both Canonical's and the community's," he wrote. "We also have retained the focus on keeping the up-to-date tools available on Ubuntu for developers, and on delivering a great experience in the cloud, where computing is headed."

We wrote about Ubuntu starting to gain traction on servers back in 2008 in some of our coverage about the rise of free community-driven distros. A growing number of large Web companies have internal Linux expertise and don't really want or need support contracts from a major Linux vendor. There seems to be plenty of room in the market, however. Red Hat, which is approaching a billion dollars in annual revenue, still has a very robust business despite losing some ground to free distributions.

Among the large-scale adopters of Ubuntu on the server, one of the biggest is the Wikimedia Foundation, which transitioned Wikipedia to using Ubuntu in 2008. According to W3Techs, other popular sites that use Ubuntu include the Internet Archive (which hosts the Wayback Machine, among other things), Twitpic, and gossip news site TMZ.

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