RAID56 under Btrfs has some caveats but I'm not aware of any annecdata (or perhaps I'm just not searching hard enough) within the past few weeks or months about data loss when those caveats are taken under consideration.
Yeah this is something that makes me consider trying raid56 on it. Though I don't have enough drives to dump my current data while re-making the array :D (perhaps this can be changed on the fly?)
I'll have a look, thanks! I guess failing this will make me test by backup strategy that I have never tested in the past.
For btrfs specifically there is an online calculator [1] that shows you the effective capacity for any arbitrary configuration. I use it whenever I add a drive to check whether it’s actually useful.
1: https://carfax.org.uk/btrfs-usage/?c=2&slo=1&shi=1&p=0&dg=1&...