I take my old drives and put them in a RAID1 btrfs volume that serves as large back-up volume consisting of miscellaneous drives. I only need that volume when

I take my old drives and put them in a RAID1 btrfs volume that serves as large back-up volume consisting of miscellaneous drives. I only need that volume when my main drives fail, and then one other drive in the btrfs volume fails. Seemed like a good idea years ago. Nowadays after watching the btrfs mailing list, I think the day I have to test the RAID1 redundancy will be like Russian roulette.