adrift in the sea of experience

Sunday, January 17, 2010

Building a NAS, part 1: installing Lenny and introducing BTRFS

I'm building a NAS from spare parts. The basic system is an 8 year old PC. My operating system of choice is the latest stable release of debian gnu/linux, codename lenny. I would like to use the (still experimental) btrfs file system on this box for the following reasons which make it a good data-haven:

  • It can do raid1-like mirroring of data over multiple devices. This makes it resilient against failed disks.
  • It can make copy-on-write mountable snapshots of a volume. By regularly making snapshots (e.g. from a cron-job) you can keep old versions of your data without wasting any space on identical copies.

Of course, this still won't fully protect my data. There could be hardware or software errors that destroy the data on all disks. There could be circumstances that destroy all disks together, like fire or lightning. So I'll still have to make an off-site backup every now and then.

To install lenny, I downloaded the 40MB businesscard CD image. Despite its small download size, this CD still has a user-friendly graphical installer. After letting the installer do its thing, I still did the following:

  • ran "tasksel" to install "file server" related packages
  • ran "aptitude install openssh-server" to enable remote access

At this point I have a basic linux system that I can SSH into. Unfortunately "lenny" does not come with btrfs support. We'll fix that in the next post...

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