Jamie Zawinski's (of the famous jwz.org) strongly-worded advice about backing up your hard drive may be a useful kick in the pants for all those too-many souls who just refuse to get the message. You must back up. But the author is a little weak on the details.

The article is from 29 September 2007, but I'm bothering to nit-pick it now because I've noticed a few recent links to it. The author recommends rsync to duplicate the disk. This is a great piece of software that I use many times a day. But it is best suited for copying files; to duplicate an entire disk or partition, dd is the appropriate tool. It will copy all the bits, so one need not worry about all the little quirks of the various versions of rsync: will it copy my resource forks? my Finder information, and other file metadata?

The flags given in the example only make sense for some versions of rsync (for example, version 2.6.3 that comes with OS X 10.4 in /usr/bin) : the "-E" flag is there to copy resource forks and file metadata, but it doesn't work quite right: see the discussions linked from this page. Also, use of the "--delete" flag means that files accidentally deleted from the working disk will be erased from the backup: this is a weak backup strategy overall, but may be ok if you use some kind of versioning system with it.

The article claims that the disk duplicated in the manner prescribed will be bootable, but that is not generally true: it depends on a few details, including what kind of Mac you are using.

The necessity of creating an off-site backup is acknowledged, but the Mr Zawinski's routine will maintain one that is a few months out of date. For work that you care about, you really need to follow a practice that will create both local and off-site copies that are made whenever the work changes significantly, which may be every hour; once per day or month is certainly not good enough.

The whole problem of backup and restore should be much simpler for naive users than it is; it should be painless and automatic, and a drive failure should never be a disaster. Unfortunately, users must still do their own research and educate themselves. I've collected some links that might be useful. The "Time Machine" that comes with OS X 10.5 may be just the thing to finally get the average user to back up, at least when a second drive is plugged in. It will be interesting to see how it fares in the field in the coming months.