midtoad's blog

Thinking about backups

I'm thinking a lot about backups this week, ever since one of my external drives was corrupted after I shut off the power on my unresponsive Mac. And in looking around on the internet for information on this topic, I'm noticing a trend.

More and more of us are storing massive amounts of data on hard drives. With storage costs plummeting to well under $1/GB, it's becoming more frequent for music lovers to put their entire collection on a hard drive, as I did a couple of years ago. This has the benefit of allowing you to browse all of your music with a few mouse clicks. But, there's a big price to pay for this convenience: if your hard drive develops a problem, you could lose your entire collection.

Then too there's the proliferation of digital cameras. I purchased my first one in 2000, and since then all of my picture-taking has been digital. All of my photographic memories are now on my PC. I'm vulnerable to hard drive defects!

I thought I was okay with a main large, external drive for storing my music and photos, and two backup drives, one for my music and one for my photos. BUT there a couple of flaws in my plan.

* My backup drives are not connected to my PC, so as a result my data is not being backed up on a regular basis. I put the drives away when I'm not running a backup, in order to guard against the possibility of theft: someone could break into my house and steal my computer and hard drive, and I'd lose all of my photos (the music is replaceable, my photos are not). * I have no real way of guaranteeing the integrity of the backup drive. As I discovered recently when I tried to restore my data from the backup drive, about 1-2% of my music files were corrupted on my backup drive. Worse, the zipped archive files (one for each year) had errors, thus making it impossible to restore them. It's a bad idea to compress your backup files for this reason.

So what I'm now discerning is that reliability and transparency of the backup process is primordial. I need to be able to back up my files on a daily basis, and I need those backup files to have unquestionable integrity. A better solution is needed. Enter the hardware manufacturers.

There are a number of NAS units coming on to the market now. Network Attached Storage is a concept whereby you connect a (usually) large amount of storage to your local home network so that it's available to any PC in the home; anyone in the network can back up her files to the NAS. Unlike external USB drives, which connect directly to one PC, the NAS unit can be hidden anywhere in the home, so long as it has a network connection.

But there's one other distinguishing feature of NAS units: they usually feature two drives in parallel, providing RAID1 security. The unit writes out two copies of your files, one on each drive, and the software or hardware in the unit ensures that both copies are non-corrupted.

The D-Link DNS-323, pictured above, just released in the U.S. and not yet (as of September 1, 2006) available in Canada, is a good example of a NAS. It's the size of a small toaster, with two slots in the back where you can slide in two drives of whatever size suits your fancy (I'll be using two 250GB drives which cost less than $90 Cdn each). A similar unit is made by La Cie. (There's a competing product made by Netgear, the SC101, but it's NOT recommended as it requires you to connect it to a Windows PC in order to run, and is not compatible with Linux or Mac OS X PCs).

At the moment I'm building a NAS using a low-end PC I have laying around, and a copy of FreeNAS, but eventually once the D-Link unit becomes widely available, I'll be installing one of them. It should cost around $250 sans hard drives.