Using disk from My Book Premium Edition II in an external caddy


I have two disks in my MBPE2, “A” and “B.”

“A” is good, and “B” has gone bad. Both are Apple HFS±formatted, in a mirror configuration. The disk pack is a TimeMachine volume.

I’ve pulled disk “A” for use in an external drive caddy–and cannot mount the disk.

Any ideas on how I could at least temporarily mount this disk to copy its data would be appreciated. I’m not above going after this with dd and friends, but I’d prefer to use a less drastic approach first! :slight_smile:


If you were using that drive in to mirror configuration, you might need to replace the drive that went bad and rebuild the RAID to recover your information.

It turns out that WD seems to use a sort of soft-RAID in their MyBook units. I didn’t realize this upon buying the unit, and would not have bought it if I had realized this; I can soft-RAID via any OS I use or have used for quite some time.

In other words, configuration information is stored on the disk rather than being handled by the hardware controller, and if one of the disks goes bad, your data is effectively gone until you replace the failed disk.

After further investigation, I agreed with you.