I get half of the raw capacity, so 7.5TB. Well a bit less due to metadata, 7.3TB as reported by df (6.9TiB). For btrfs specifically there is an online calculat

I get half of the raw capacity, so 7.5TB. Well a bit less due to metadata, 7.3TB as reported by df (6.9TiB). 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&d=4000&d=4000&d=3000&d=3000&d=1000 https://carfax.org.uk/btrfs-usage/?c=2&slo=1&shi=1&p=0&dg=1&...