When Sun announced a major open source initiative targeting small and midsize businesses this week, a lot of people failed to realize that Sun would include servers certified for Ubuntu. Here’s the scoop, from our sister site, The VAR Guy (www.thevarguy.com).

Sun’s SMB move comes only a day after The VAR Guy predicted server vendors would up their Ubuntu efforts by May. Of course, it’s important to keep the Ubuntu victory in perspective. Sun also is promoting SMB servers certified to run Windows Server, Solaris, Red Hat Linux and Novell SuSE Linux. (Here’s a closer look at the product lineup.)

Still, Ubuntu is mooovin’ on up from the desktop to the server. A major Ubuntu release, code-named Hardy Heron, will contain several significant server-focused enhancements when it arrives in April. As The VAR Guy has pointed out, Ars Technica offers readers a pretty comprehensive look at an Alpha release of the operating system upgrade.

Sun also is sponsoring Ubuntu Live, a conference in Portland, Oregon this July. And Sun’s MySQL business has been a vocal supporter of Ubuntu.

Taken together, these developments reinforce Ubuntu’s promise on the server. But Ubuntu remains an upstart of sorts, since Red Hat continues to dominate much of the enterprise Linux market and Novell showing some respectable momentum in recent months. (Check out The VAR Guy's Novell BrainShare coverage for more on that company’s strategy.)