
let me back up a bit and explain. I have a Mac Pro, 32GB.
I created a 3TB x 3TB x 3TB Raidz called Ocean, with a Dataset called Home.
NAME USED AVAIL REFER MOUNTPOINT
Ocean 3.09Ti 2.28Ti 51.8Mi /Volumes/Ocean
Ocean/Home 3.09Ti 2.28Ti 3.09Ti /Volumes/Ocean/Home
I rsync'd my OS X home folder contents to 'Home', changed my advanced user settings, and rebooted. Everything worked fine. My home was safely on my ZFS dataset. I copied over the rest of my files to it using rsync, took about 2 days.
Everything seemed fine until I needed to restart my computer. When it booted up, and i logged in, i basically got the OS X setup wizard. uh oh. My home dataset was gone.
actually, it's still inside Ocean, but every folder (except Library, which I assume was created anew) is now empty. Basically like a fresh OS X installation.

I headed over to terminal and did zpool status and got this…
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NAME STATE READ WRITE CKSUM
Ocean ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
GPTE_4623BE4C-B931-42E3-B086-1AB4B7C25AD8 ONLINE 0 0 0 at disk2s2
GPTE_E438C301-7879-49CB-8E09-22B734793326 ONLINE 0 0 0 at disk1s2
GPTE_608CE13A-017D-4EE6-803F-18429C27904A ONLINE 0 0 0 at disk0s2
errors: No known data errors
OK, THAT SEEMS NORMAL.
---
Then I did zfs list and got this…
Ocean 3.09Ti 2.28Ti 51.9Mi /Volumes/Ocean
Ocean/Home 3.09Ti 2.28Ti 3.09Ti /Volumes/Ocean/Home
OK THAT SEEMS NORMAL TOO. HMM.
---
I also have a snapshot from right before I restarted, that is still listed
NAME USED AVAIL REFER MOUNTPOINT
Ocean/Home@2012-09-20 10.7Ki - 3.09Ti -
YEP, LOOKS NORMAL. SO YOU'D THINK FROM THESE 3 POSITIVE SIGNS, THAT I COULD SALVAGE THIS RIGHT?
I tried rolling back to this snapshot, and restarting, but it did nothing. I can't even see a .zfs folder inside Home. I toggled the visibility to on, but it did nothing.
THE CRAZY THING IS, inside the Ocean disk, the 'Home' icon is now just a folder. It is no longer showing up as a ZFS volume via Get Info. I created a test dataset, Ocean/Test, and that mounted on the desktop just fine, and it sits inside the Ocean volume as a nested volume, just like Home USED to do. 'Test' also has a .zfs folder.
I thought that if I have raidz redundancy, I can rebuild from a fault like this. PLEASE tell me this is the case. And if so, how? I am currently scrubbing to see if that helps.
I DO NOT have a backup. I created a new backup pool from my *original drives* that I copied the data from initially, and was just about to send / receive everything back to them when this happened.
ARGGGHHHHHHH.
If this is any help, my mac updated me to 10.8.2 earlier today. zfs seemed to be working fine on that, although I guess it could be a bug.
Just please tell me my data is still there. If I just can't see it for the moment, I can live with that.