Is your computer backed up? Are you 100% confident your backups are complete and up to date?
I didn't think so.
Here are rules for a secure backup. Trust me — it's not difficult to do well.
1. Like exercise, the best backup is one you will actually do. Automation is essential, unless you are very disciplined.
2. You need two! You never know a backup is bad (corrupted, missing, has been failing without your knowing it) until you need it.
3. Best is to have two using completely different mechanisms. For instance, one might be a copy that runs via a nightly script and another could be a backup program, and each goes to separate media.
4. One should be a total backup (so you can recover everything on your disks and be up and running quickly); the other can be just essential files. The total backup should be hard-drive based.
5. You should have something offsite. You may neglect this, thinking it's only in case of fire, which is not so likely. But you should also think of theft. If a thief takes your computer, they will probably take your USB drive and may scoop up any CDs or DVDs they see. Imagine the relief of having the key files elsewhere. Or the grief of not having them.
This can be a much smaller set (e.g. your e-mail, docs folders, omitting system files and applications). The easy way is to use an online backup service that stores your key files on their servers. There are many. Some are designed as backup (like mozy.com or crashplan.com); some are automatic file or folder sync tools (like dropbox.com). These programs all work with Macs and Windows. Some are Linux-friendly, too. I haven't tried it yet, but Crashplan looks great and you can use it to manage the whole family's backups.
If you don't want to fuss, just go to mozy.com and have at it.
6. You can use a USB or FireWire external drive, or a separate drive mounted in another computer on your local network.
I use EMC Retrospect as my primary. It backs up all the Macs and Windows on my network to multiple sets and supports DVD. I have two DVD sets, one of which is in the office.
My secondary is SuperDuper (for Mac) which mirrors the whole drive to a separate disk (you can use the similar Deja Vu or Carbon Copy Cloner).
If you're observant, you'll note I am violating my own rule 5. One of these days soon....
Apple's Time Machine is another great choice for those with recent Macs.
If you have suggestions for backup programs or services, please add a comment.
Revised March 2010