Cryptosmith

Two things about my computer use over the past decade: 1) I’ve been moving all of our family mementos (mementi?) to digital form, and 2) I’ve become a total klutz about mass storage. A disaster in the making? Almost, but not quite. I’ve spoken earlier about using RAID on my Mac Pro, and now I’m using RAID with my Time Machine storage. I use my drive swapping trick to create backups, and keep the backup off-site.

While performing the drive swap, I managed to smash my working OS X system partition. Thus, I got to experience first-hand the process of recovering my system from my Time Machine backup. Here’s the report.

[UPDATE: Since the original posting, I've found more brittleness in the restored Aperture directory and I've been negotiating a truce between Paragon's NTFS and my NTFS-formatted portable USB drive. Sides are still not quite on speaking terms.]

I wiped out the file system on my working OS X system because OS X is stupid when it comes to handling extra RAID volumes. Once it has marked a volume as belonging to a RAID set, it is almost impossible to convince OS X that it’s not already part of that RAID set. The only thing that has worked reliably is to boot Windows, run the DOS shell, and run the diskpart command to zero the old partition headers. This blasts away all evidence of having been part of a RAID set.

This particular occasion was to celebrate the receipt of a new hard drive, which led to a rearrangement of other drives. I use a mirrored RAID configuration with Time Machine. To create a back up, I unplug one of the mirrors, stash it in a safe place, and rebuild the remaining mirror onto a blank drive.

Using Boot Camp, I booted up my XP partition and fired up the DOS shell. I used one of those SATA to USB connector cables to connect the replacement drive, but I managed to set it up incorrectly. When given a choice of unnamed volumes to blow away, I chose the wrong one. Because of my cabling error, the right one didn’t even show up.

Once I realized my mistake, I used ProSoft’s Data Rescue II to try to salvage the original files. At first I had mistakenly assumed that Data Rescue might be able to restore the directory and boot records, but that’s not the sort of tool it is – Data Rescue is very careful not to change the damaged volume. I used Data Rescue primarily to recover my Aperture photo library – Aperture is cleverly designed to put the library in One Big File, so any time you change anything in your Aperture library, this monster file has to be written to Time Machine. (And I really didn’t want to try rebuilding my library from the Aperture “vaults” except as a last resort).

Then I retrieved my OS X install disk and ran the install on a clean and larger drive. The install program gave me the choice of restoring from Time Machine and I took it. A few hours later, my system was bootable again. But not entirely functional.

Here are the things that broke, and I suspect the list isn’t finished yet.

• The biggest problem was that the Boot Camp bootstrap went away. Apparently the only way to restore it is by installing Windows again. I sacrificed a spare hard drive to start that process, and that proved to be enough to restore a working bootstrap.
• My printer software all appears to be installed, but the printer configurations all evaporated. I had to do “add printer” on them to make them usable again. I haven’t tried my scanner software yet. It’s from HP so I expect the worst.
• Aperture did badly.
  • The application itself didn’t work, even after I restored a copy of the original library. It wouldn’t even start up. I had to reinstall it and reapply patches.
  • (UPDATE) Since Aperture insists on organizing everything around a gargantuan “library” file, I keep the master photo files separate. However, it turns out that Aperture, having been written by people that knew far more than was good for them, decided to link to the original files using an internal file reference instead of simply using the file name. Thus, when you restore the system onto a new drive, all the file references are wrong. Fortunately there is a special command that will link images in the directory back up with their files.
• Paragon NTFS no longer recognizes my Boot Camp partition. I installed Paragon’s software so I could easily sync folders between the two systems.
  • After the restore, however, the Boot Camp partition falls back under control of the OS X file system, which provides read only access. Annoying, but not show-stopping. I haven’t tried reinstalling or any other tricks to make this work again.
  • (UPDATE) Paragon started working again after I installed the latest update, which is essentially the same as reinstalling the software. However, it doesn’t recognize my portable USB drive, which is NTFS formatted. I mean, the thing simply doesn’t appear under OS X. It seems to work fine under XP.

Despite the hassles, it’s much better than having to restore a PC system. I haven’t needed to reinstall applications wholesale, an infuriating process.

One remaining question: how can I keep from making the same mistake again? The diskpart user interface is designed to make this mistake easy and perhaps inevitable. One approach is to use a different Windows system – one that doesn’t also include my working data. That’s not especially convenient, but it is safer.

Posted under Security | No Comments »