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17 December 2006

Nerd Factor X



Easing into Ubuntu

Here are some short notes on the Ubuntu experience, plus a revelation about virtualization.

First, Ubuntu. After the initial teething troubles it has been going pretty well. I'm getting used to some of the filesystem quirks (sorry but web content should not go in /var, dammit!).

Also the package management is good but a little disappointing. Bear in mind that I'm coming from FreeBSD where it is very rare to compile third-party software from a tarball. On Ubuntu I've had to do it several times now (eg Subversion 1.4, Ruby Gems).

On the plus side the forums are fantastic so there's almost always help available.

So migrating my applications from the old FreeBSD server to the new Ubuntu server has been slow going. But I'm getting there. For the duration I've been running with both servers powered up, and as I start up an application on the new server, I shut it down on the old.

Recently though I had a revelation. Instead of keeping the FreeBSD server powered up all the time, why don't I just make it a virtual server running within Ubuntu? In contemplating the physical-to-virtual migration it also struck me: virtual machines are a great way to test your backups.

We all do backups, but how often are we likely to test them in an all-out completely from scratch re-install? Hardly ever, because you generally can't spare the hardware. Now, it's easy!

So as we speak I'm going through Mark Hannon's excellent HOWTO restore a FreeBSD system using the fixit CD, with a couple of tweaks for the virtual environment. Getting the backup files into the virtual system is a problem because within the fixit environment there is no access to networking (or at least nothing easy that I could see). So instead I made an iso image containing my backup files using mkisofs, and mounted that on the second CD-ROM drive of the virtual machine. Easy.

I plan to get this new virtual server up, switch over the DNS CNAME entries from the old server to the new, and power down the old FreeBSD server for good (or until eBayed to raise funds for the imminent RAM purchase that is now required by running a virtual machine).


Posted by
Sunny Kalsi
2006-12-17 04:50:07 -0600

exactky why is it a bad idea to put web content in /var? and if not /var, then where?

Posted by
2006-12-17 04:50:07 -0600

/var is for "multi-purpose log, temporary, transient, and spool files", at least according to man hier on FreeBSD, which is where I get my expectations. This FHS agrees:

/var contains variable data files. This includes spool directories and files, administrative and logging data, and transient and temporary files.

Admittedly there is stuff in there which doesn't meet that description, like crontabs, but for the most part it's pretty accurate.

In my mind /var is somewhere where the most frequently-changed stuff goes, and often deserves a completely different type of filesystem. For example, on my OpenWRT box, /var is stored in RAM to avoid excessive write cycles on the flash storage.

I would say /usr/www or /usr/local/www is the place for web content.