Now, five months later, Netcraft's July Web Server Survey confirmed this decline: Apache again lost ground to Microsoft Internet Information Server (IIS).
In July, Microsoft added 2.4 million sites, bringing the total number of Windows Server sites above the 40 million mark, Netcraft found. Microsoft's market share also received a boost, increasing 1% since June to reach 32.8% overall. Apache saw an increase of approximately 556,000 Web servers, but its market share declined by 1.1% to reach 52.6% overall.
On the face of it, the numbers represent a consistent month-over-month decline for the world's most popular Web server. But experts aren't ready to call this downward trend a watershed moment yet.
Apache Tomcat and Google: A closer look
Mark Brewer, CEO of Covalent Technologies, an Apache support provider based in Walnut Creek, Calif., blamed part of the decline on Apache Tomcat, a Web container developed by the Apache Software Foundation, which also created the Apache Web server. According to Forrester Research Inc., 51% of enterprise-class production-level deployments run Tomcat.
In this light, Brewer said the gradual decline is not attributable to competition from commercial proprietary alternatives like IIS, but rather to the rising number of Tomcat production-level deployments.
"When doing a Netcraft lookup on Web sites that are known to be using Tomcat, [the search] frequently does not report as Apache," he said. Examples include the JBoss site, the Sakai site and Wal-Mart Stores Inc.'s digital photo center Web site, he said.
Additionally, Brewer said most Web sites that use Tomcat to serve up Web content via HTTP would show up in surveys as a "mod_jl.conf" entry -- not Apache -- and thus would not be counted as sites that use Apache servers.
"Add to that the fact," he said, "that any Web site being proxied with something else in front of it would not accurately show what's really running the show behind the scenes -- IIS, for example -- and another reason for the decline is clear."
Observers cite other reasons for the shift as well. Tony Iams, an analyst with Rye Brook, N.Y.-based Ideas International, said Apache's decline is due in part to a recent Netcraft "reclassification" of what constitutes an Apache Web server.
"Netcraft originally classified Google servers as Apache machines," Iams said. But earlier this year, the firm began reclassifying these servers in their own unique category, which affected Apache's market share, he said.
According to the Netcraft report, the Google server category gained 592,000 Web sites in June, and market share was 4.4%.
But this reclassification still doesn't explain the increase in IIS instances, Iams said. For that you have to look at Microsoft's activity with Vista and virtualization.
"One of the new features in Vista is [IIS7 in Longhorn Server Beta 3], and so that has put a few people on Vista machines and would start to show a change in market share," Iams said. According to Microsoft, IIS7 is now available for customer testing under the special Go Live License, which permits customers to deploy beta releases of IIS7 into live production environments before the official release of Windows Server, also known as Longhorn Server, which is due out in 2008.
According to Iams, Microsoft has been aggressive in generating interest in IIS7. Its strategy includes more flexible licensing such as Go Live and the decision to allow users to run virtual machines. "Users can now run multiple copies of Windows on the same server," Iams said, "and that's made it a little easier for hosting providers to set virtual servers."
Microsoft's Longhorn Server impact
When Microsoft Server 2003 launched, Netcraft showed no discernable boost in market share. Iams expects that trend to continue in 2008. "It's fair to assume there will be some uptake, especially if companies are holding off on upgrades today," he said. "But if you look at Netcraft's numbers when [Server] 2003 came out, it didn't help IIS at all." Instead, it actually hurt IIS' numbers, he said.
If this historical trend is to be believed, in 2008 the phenomenon may repeat itself. Iams said many companies installing new Web servers are in a "Web 2.0 phase" and want quality servers up and running as quickly as possible with minimal downtime.
The practice bodes well for Apache, which, according to Dutch Web monitoring firm WatchMouse, is leaps and bounds ahead of IIS in terms of quality, uptime and Web site load times.
Whether it translates into another shift in market share next year is still open to debate, Iams said. With the Apache decline, "there's not really any one thing to point to right now; it's a confluence of any number of things," he said. "Microsoft has certainly recognized the importance of having that larger footprint, and they're going to work very hard to maintain it."
Email Jack Loftus with your comments and suggestions.