A Linux server OS that's had 11 years to improve
Is SME Server ready to roll?
Unfortunately, SME Server omits a few features that its rivals supply as standard. Many of these things can be added on via third-party packages called "contribs", such as web-content filtering using DansGuardian. However, this requires a little more effort from the administrator, which is what these distros are aiming to minimise. For instance, SME Server has little meaningful groupware support out of the box. Users can email each other, of course, and if their client supports workflow then this will work over POP3 or IMAP.
If you tried SME Server back in the Red Hat days, it's changed and is still improving. There are new and improved facilities for backing up to USB devices attached to the server as well as to workstation hard disks, as well as an integral system-updating mechanism built into the admin web-GUI. The optional loginless server control menu on the server console has disappeared, replaced by a bare login prompt, closing a potential security hole. (The admin menu is still available if you log in as “admin” - the same password covers root, admin and the web interface.) However, SME Server 7.5 is not all that current – for instance, it uses Linux kernel 2.6.9, which is pretty ancient by 2010 standards. This reflects the conservatism of CentOS and its underlying Red Hat Enterprise Linux, but the upside is a long lifespan in terms of security updates.
We also had a quick look at beta 6 of SME Server 8. Upgrading is very easy – boot from the new version's CD and install over the top. All settings and data are preserved and it works exactly as before. It uses a tiny bit more memory, but not to any significant amount, and is largely indistinguishable, although on our test machine, Apple file services stopped working after the upgrade.
SME Server is admirably simple and it does what it says on the metaphorical tin. It's superbly easy to install and maintain, client PCs or Macs can be connected in minutes, it's reliable and robust and needs very little maintenance. Getting it working requires less work or specialist knowledge than either ClearOS or Zentyal, let alone to Windows SBS.
The ability to mirror a pair of disks in your server for greater resilience is a nifty touch, too. For a simple small business, it's just the trick and is perfectly capable of supporting dozens of users with no real hassle at all – and the flexibility and low-resource-usage of Linux makes hundreds of users on a midrange server entirely feasible, should your organisation grow so much. It's also completely free, with no accounts or registration required, and the support forums on the contribs.org site are helpful.
It doesn't have many downsides. There's no modularity – you can't remove features you don't need. The domain-controller feature of the current version is not fully compatible with Windows 7, although SME 8 will fix that. It doesn't have as many traffic-management features as ClearOS, nor Zentyal's groupware support. Find our in-depth reviews of ClearOS here and Zentyal here. ®