Big Bad Blog : film and photography.

Normally, this blog is reserved for BBP projects and things of a photographic nature but I wanted to share my experience with a recent problem I had and solved.

I accidentally deleted my striped raid array in Disk Utility. This meant that I lost both my most recent work — and some older work that I had not yet backed up.

I called Apple Tech Support, who confirmed my research that it was not easily possible to recover from this mistake.

Because the disks were undamaged, and the files uncorrupted this method was possible. In other cases this might not work. Here’s the method I used to get my data back:

1. Recreated the raid array in disk utility using the same name, block size, disks and raid type.
2. This left me with a “blank” raid array that Mac OS could now recognize.
3. I promptly unmounted this array to prevent overwriting it.
4. I then used Prosoft’s Data Rescue II ($99 — worth it) to recover the files on the disk.You’ll want to use the “thorough” method and be patient. It took about 2 hours to scan my 600 gigabyte drive. You might also want to increase the maximum filesize it will look for if you have some large files (like video or digital medium format) otherwise it will cut them off (the default cutoff is 100mb I believe)

Of note to photographers is that Data Rescue can support Flexcolor format(.fff) files  as well as Photoshop and Canon Raw formats– this is important with this recovery method because without any way of determining file structure from the file allocation table the software searches the disk block by block for specific file types. I wasn’t able to find any other software that supported .fff format — so if you shoot with a Hasseblad and use a mac you might want to bookmark their website.

In order to enable Flexcolor support for Data Rescue you have to email their support guys and ask for it — as it doesn’t seem to be included by default yet.

When I was googling for information I didn’t find much on the topic, so I thought I’d help out and post my experience. There are also some free software alternatives in the form of Forensic oriented software for highly technical users. Check out the Helix Livecd made by E-fense. You can use the software package PyFlag to attempt to recover your raid array — it can actually attempt to reconstruct the filesystem — but currently doesn’t compile easily on a mac — and the Livecd currently won’t boot on a intel mac due to a Grub incompatability. I hope this helps — and please post any extra information or corrections.