How to UN-raid a formerly Raid-ed drive?

[Paul F.]

So... I've got these three drives that once inhabited a RAID. I suspect there was a fourth drive, which I didn't get.

Upon insertion into a Mobius 5 bay case (which is set to JBOD, with four other drives of various sizes in it), any of the drives shows in Disk Utility as a 12Tb RAID, which, it probably used to be.

But, trying to partition or erase the drive is a problem... it (DiskUtility) cannot be convinced it's not, as a single drive (and I've tried this with each one of the three), a 12tb volume.

How do I "low level format" this drive, block by block, so it's re-created as a single volume/partition?
Or should I just chuck these otherwise perfectly good (ish) drives?

[GGD]

Have you tried using a Snowleopard system and Disk Utility from that. I think it's from before CoreStorage and might not have any nanny features protecting you from yourself.

If you have a 10.6.3 install DVD and old enough hardware you shouldn't even need to install it, just run Disk Utility from the DVD, put the drive into a USB or FW enclosure, erase it, shut down, and move on.

Or maybe try something similar from a Windows or Linux system.

[Paul F.]

GGD wrote:
Have you tried using a Snowleopard system and Disk Utility from that. I think it's from before CoreStorage and might not have any nanny features protecting you from yourself.

If you have a 10.6.3 install DVD and old enough hardware you shouldn't even need to install it, just run Disk Utility from the DVD, put the drive into a USB or FW enclosure, erase it, shut down, and move on.

Or maybe try something similar from a Windows or Linux system.

Good thought! I did try formatting from a Linux virtual machine, but it returned the same 12tb volume size and "Unable to write to the last block of the device" error that DiskUtility (Yosemite) returns.

It may also have something to do with the case I'm connecting it to... I need to see if I have any other SATA bridge, or empty case I can strap it in, and try it.

[Filliam H. Muffman]

Hook it up directly to a Mac motherboard and format it.