I have a 4tb zfs mirror which is difficult to mount because of a problem that occurred when it was first made. I think the best way to fix it is just to start over.
My idea is to pull one of the disks from the mirror, create a new zfs pool on that disk then move everything from the original on to the new one and add that disk to the new pool as a mirror. Will this work?
I I wasn't sure if you could create a mirror without wiping the data but there's no problem. Just copied the data from the old degraded pool to the new single disk pool then ran zpool attach to put the old disk in to the new pool and it resikvered it into a mirror no problems.
Real quick, could you just post the result of a zpool status for me right quick? I can see how setting up a mirror after the fact would theoretically be possible, but I worry. In your screenshot above, you have
That command just created a single disk (non redundant) volume called zpool 1 on /dev/mapper/downloads1. After that I used syncoid (which uses zfs send / recv) to copy the data from the original (degraded) pool on /dev/mapper/downloads2.
Once that was done I exported the original pool and ran:
For people interested in re-purposing zpool disks: you can use "zpool labelclear /dev/......" to clear all ZFS labels on a disk. That gives you the extra dot of certainty it won't get mixed up e.g. if you have to mount it inside a machine and cold boot it.