[David2213]

I have 2 1TB 3.5" Seagate Hard Drives in a Sans Digital external closure. When i came home today i turned it on and nothing mounted. I opened up disk utility and where the two drive should be all that showed up is one that said raid slice.

Any suggestions about to get the whole thing to mount?

Thanks for your help.

[tooki]

Either one disk failed, one's connection is loose, or one's controller failed.

How are they RAIDed? Apple RAID? SoftRAID? Hardware in the enclosure?

[David2213]

i used disk utility to do the raid. is there any way to pull the data off of the discs one at a time while they are formatted this way?

[tooki]

There are two ways to combine two 1TB disks to make 2TB: RAID 0 and concatenation (JBOD). If you did JBOD, you might, maaaybe be able to recover something with special software. If you used RAID 0 and one of the drives failed, you're screwed, because half of every single file lives on each drive, so if one drive fails, you lose everything. (And that's why RAID 0 cannot be relied upon, you MUST back up to somewhere else religiously.)

If you did RAID 1 (where data is mirrored, but you only get the space of 1 drive) you should be able to recover with no loss.

Before beginning to sob or freak out, let's eliminate the drive enclosure as the problem. If you have another external housing (or access to a Power Mac G5 or Mac Pro), see what happens if you put each disk into it.

I just thought of another potential failure point: the external housing's power supply. That type of power supply is proving to be somewhat unreliable, and if it's beginning to fail, it's possible that it's only putting out enough juice to spin up one drive, not both. Again, test with another housing.

[David2213]

Thanks for the help. I will pick up another drive enclosure this afternoon. Do you have any recommendations? Luckily the files that were on there were not irreplaceable.

[tooki]

I've used ones from MacAlly and from Other World Computing.