Recently, I had to futz with an Ubuntu server that was to run mail, web, and database services.
You slowly learn that Ubuntu as a desktop is easy to use, but as a server, its “different”, if you come from a Red Hat based background (especially if you’ve been using Red Hat-based distributions for the last thirteen years or so).
From example, while service httpd start works (well, the equivalent is service apache start), enabling things on boot using chkconfig (I wrote about it a while back) is replaced with update-rc.d.
In fact, if you’re an rpm aficionado, dpkg is a little different. I applaud the Ubuntu folk for creating an article such as Switching to Ubuntu from Red Hat Enterprise Linux or Fedora. Impressive. Switcher guides :)
OpenSolaris needs switcher guides. svcadm/smf is different for someone who’s coming from Linux-land.