A Quick Restorative
A while ago I wrote a short HOWTO that describes how to back up a Mac OS X system to another drive using rsync. This was not for the pure academic enjoyment of it, it's what I use to back up my sidekick PowerBook, and I recently got to see how well it worked when The Worst Happens.
Actually, the worst would probably be the laptop being stolen. What actually happened is, without warning, the hard drive lapsed into brick mode. In the short interval between being the heart and soul of the PowerBook and becoming an interestingly-shaped piece of metal, it started making strange noises. Being a professional computer geek I knew what this meant and wasn't even that surprised—laptop hard drives are notoriously fail-prone and mine had been spun up and down several times a day for 2 1/2 years plus the usual knocks laptops get when travelling. And there's that warm glow called Extended Warranty.
What did surprise me was that even while I could hear the HDD dying, the SMART status readout in Disk Utility confidently continued to read "Verified". Some recent data from Google (PDF) and the blogs that popped up in response seems to indicate SMART just isn't very reliable for detecting when your drive is about to fail—here's another data point to back that finding up.
Anyway, when the drive started coughing, I tried to get some recent data off it, which just accelerated its demise. So I booted off the external backup drive and had my system back. I was just about to start feeling smug when I realised I hadn't backed up for nearly six weeks. Irritating, but I hadn't lost much and still had a working system to use in the meantime. A bootable backup is a must-have IMHO, you can limp along with this in the time between it being fixed. Commercial systems that create non-bootable backups are really hobbled in this regard.
A week in the AppleCare hospital later and it had a new HDD. Reverse rsyncing from backup took about 2 hours and, after some messing around with the "Startup Disk" preference pane (the "bless" command didn't seem to stick for some reason), the machine booted and I was back to December 27, 2006 in PowerBookLand.
So the backup and restore system worked. I really can't even begin to estimate how long it would have taken to reinstall Mac OS X, download 100's of MB's of updates and applications, reinstall Office, XCode, Eclipse, etc, tweak my settings, restore music, contacts, calendar, photos (assuming I had those), ...
The more I think of how many things most people don't back up which cost them so much time and energy to set up I find it astounding. Of course there were three things in my favour
Because Mac OS X doesn't assume you're a pirate and require an activation scheme to prove you're not one (such as that used by some other companies which I won't mention but which sound like "Microsoft") it makes it possible to clone the system without the OS working against you. This is something I really appreciate about Mac OS X.
One thing that didn't work was resource forks. None of these got restored because, as it turned out, none were being backed up. I just didn't check—when the system booted of the backup and everything appeared to work I naively assumed resource fork backup must be working. However the reason the backup worked is that almost no software seems to rely on them anymore.
This was irritating, since the part of the point of the HOWTO was to add info on how to preserve these. But it certainly didn't have a large effect. What tipped me off is none of the Classic apps in my old "Applications (Mac OS 9)" folder which need the System 9 emulator work any more. No biggie, the System 9 apps were interesting for historical reasons, but I came into Mac land for Mac OS X.
More annoying, none of the Microsoft Office 2004 applications run. They're not even recognised as applications any more. Neither are Carbon ports of OS 9 applications such as Graphic Converter. Still, this should be fixable, and once I've fixed them I'll start investigating why resource forks aren't making it through rsync and update the HOWTO.
Actually, the worst would probably be the laptop being stolen. What actually happened is, without warning, the hard drive lapsed into brick mode. In the short interval between being the heart and soul of the PowerBook and becoming an interestingly-shaped piece of metal, it started making strange noises. Being a professional computer geek I knew what this meant and wasn't even that surprised—laptop hard drives are notoriously fail-prone and mine had been spun up and down several times a day for 2 1/2 years plus the usual knocks laptops get when travelling. And there's that warm glow called Extended Warranty.
What did surprise me was that even while I could hear the HDD dying, the SMART status readout in Disk Utility confidently continued to read "Verified". Some recent data from Google (PDF) and the blogs that popped up in response seems to indicate SMART just isn't very reliable for detecting when your drive is about to fail—here's another data point to back that finding up.
Anyway, when the drive started coughing, I tried to get some recent data off it, which just accelerated its demise. So I booted off the external backup drive and had my system back. I was just about to start feeling smug when I realised I hadn't backed up for nearly six weeks. Irritating, but I hadn't lost much and still had a working system to use in the meantime. A bootable backup is a must-have IMHO, you can limp along with this in the time between it being fixed. Commercial systems that create non-bootable backups are really hobbled in this regard.
A week in the AppleCare hospital later and it had a new HDD. Reverse rsyncing from backup took about 2 hours and, after some messing around with the "Startup Disk" preference pane (the "bless" command didn't seem to stick for some reason), the machine booted and I was back to December 27, 2006 in PowerBookLand.
So the backup and restore system worked. I really can't even begin to estimate how long it would have taken to reinstall Mac OS X, download 100's of MB's of updates and applications, reinstall Office, XCode, Eclipse, etc, tweak my settings, restore music, contacts, calendar, photos (assuming I had those), ...
The more I think of how many things most people don't back up which cost them so much time and energy to set up I find it astounding. Of course there were three things in my favour
- I knew how much a disk failure and system rebuild would cost, having experienced this before,
- I had the technical knowledge to make a real backup rather than copy random directories every now and then, and
- I was using an OS that makes it easy to clone an entire system.
Because Mac OS X doesn't assume you're a pirate and require an activation scheme to prove you're not one (such as that used by some other companies which I won't mention but which sound like "Microsoft") it makes it possible to clone the system without the OS working against you. This is something I really appreciate about Mac OS X.
One thing that didn't work was resource forks. None of these got restored because, as it turned out, none were being backed up. I just didn't check—when the system booted of the backup and everything appeared to work I naively assumed resource fork backup must be working. However the reason the backup worked is that almost no software seems to rely on them anymore.
This was irritating, since the part of the point of the HOWTO was to add info on how to preserve these. But it certainly didn't have a large effect. What tipped me off is none of the Classic apps in my old "Applications (Mac OS 9)" folder which need the System 9 emulator work any more. No biggie, the System 9 apps were interesting for historical reasons, but I came into Mac land for Mac OS X.
More annoying, none of the Microsoft Office 2004 applications run. They're not even recognised as applications any more. Neither are Carbon ports of OS 9 applications such as Graphic Converter. Still, this should be fixable, and once I've fixed them I'll start investigating why resource forks aren't making it through rsync and update the HOWTO.
posted by Matthew Phillips at
5:25 pm
0 Comments:
Post a Comment
<< Home