July 11, 2006

A friend taking an extended road trip just had her car stolen, with her laptop and everything else in it. That sucks massively. It got me thinking about the problem of maintaining backups and having access to them in a situation like that.

My home computer is a desktop. Currently I have it hooked to an external drive, and backup software runs in the wee hours every night to copy my home directory to the external. At some point in the near future, I hope to get a network-attached storage drive, so that I can A) liberate a little desk space, and B) move the backup away from the computer, in case something happens the computer. Admittedly, I’d only be moving the backup about 15 feet away, but a black box wedged into a cramped closet is much less likely to attract a thief’s attention, and if the roof collapses or something like that, fifteen feet might be enough. That’s what I’m counting on, anyhow.

But what about when you’re on the road? You need a backup medium that you keep separate from the laptop but still have ready access to, that is reasonably fast, and perhaps most importantly, is convenient to use. What are your options?

Before you can decide, you need to get your priorities in order. Some files are more critical than others; some change more frequently than others. Assuming that you will need to make compromises, you want to make sure the most current and most critical files are the most readily available and most frequently backed up.

Exclusive of media files, my home directory is about 5 GB. I’m guessing that about 1.5 GB of that is actually cache files and other digital ephemera, so to recreate my home directory, I’d need to be able to store about 3.5 GB. This would exclude all applications, music, videos, and photos. In reality, I could probably cut this in half by omitting a lot of archival files, though to do that I would need to reorganize my hard drive considerably. I’m lazy, so let’s stick with 3.5 GB as a target.

So, what are my options?

iPod

It just so happens that I have a 4 GB iPod Nano (rumor has it that these will be bumped to 8 GB soon). This would just accommodate me, plus a few hours of music or whatever. A hard-drive based iPod would have no trouble at all; in fact, I could store my home directory even with most of my media files on a 60 GB model. The potential problems here are that I would need to be scrupulous about keeping my laptop and iPod separate, and the temptation to keep music on the iPod, even if it cut into my storage requirement.

Network

My web-hosting company gives all its customers 20 GB of storage and webdav access. Webdav is pretty cool, because it lets me mount my network storage just like a hard drive on my desktop. A really, really slow hard drive, but there it is nonetheless. If high-speed connections could be taken for granted, this would be the ideal option—putting my storage in a remote datacenter that has its own redundant backups etc. But high-speed connections are hardly universal, and even when present, the upstream rate can be pretty slow. Backup software generally only backs up files that have changed since the last backup, but even with only 10 MB to back up, over a 128-Kbps upstream line, that will take at least 10 minutes (allowing nothing for communications overhead). In terms of convenience, this can’t be beat, assuming the connection is there. Make sure the remote volume is mounted and let the backup run. This is the only option that can be run unattended and still keep the backup volume physically separate. Having it on the server means I don’t need to even use my own computer to get at it; better still would be to have it in some web-readable format so that I could read it from any computer with a web browser. Thanks to Google, a lot of people are moving in this direction anyhow. I’m not entirely comfortable with that, and I get benefits from programs that run right on my computer that I’d be unwilling to give up, but perhaps if I had a more mobile lifestyle, I’d make a different tradeoff. And I do essentially do this already with my photos, by uploading them to Flickr.

Optical storage

Most newer laptops can burn to CDs at least, and in many cases to DVD. A single-side, single-layer DVD can store 4.7 GB, so I’m in the clear there. The drawback here is convenience: you need to go to more trouble to insert the disc, set up the burn session, burn the disc, label it, put it away somewhere, hope that it doesn’t get scratched before you need it, etc.

Flash drive

While this is technologically equivalent to the iPod Nano (and comes in the same storage sizes), I see a few key differences: there’s no particular temptation to use the flash drive for music, and you can hook it to your keyring. For this reason, I like this solution best for the most critical and current data: if the drive is on your keyring, you’re less likely to leave it connected to the computer. Well, I’m less likely, anyhow. This does require me to launch the backup manually, though.

I can imagine a multi-layered approach where I use a thumb drive as my primary backup for working files, bring a DVD that I burned in advance with some critical applications, occasionally burn a CD or DVD with photos (possibly snail-mailing it home), and occasionally upload my very highest-priority stuff to the server when I can take advantage of a fast connection.