[archi42]

At home: I'm running a RAID1 btrfs on my 12 disk cold storage (rackmount, SAS backplane, JBOD SAS controller). It has two new 4TB 24/7-rated SATA disks I got for that NAS, the rest is mostly salvaged from work (old drives, 500GB to 1TB). I had exactly the same selling point on btrfs as the author - I see a "huge" 7.8TB RAID1, and once it fills up I just swap an old disk (or two) for another 24/7 disk with decent TB/$.

At work: I was told our OpenSUSEs had some failures/data-loss, so we're not using the default btrfs on these. Though I don't know with what version that was (we migrated to OpenSUSE about 3 years ago).