Given the plans to make btrfs the default, I'll share some of my own
recent experiences, hopefully this can make it easier for the next person
One issue I've come across is that a btrfs filesystem can only be used
on hosts with the same page size as the host that created the filesystem
E.g. x86-64 kernels have a 4k default page size but powerpc64le kernels
have been compiled with the optional 64k page size. This impacts
various distributions.
If somebody creates some filesystems with the 4k parameter and then they
migrate them to the powerpc64le host, they won't mount
If they try to go the other way, the filesystems won't mount either
There are other non-btrfs issues related to the 64k page size, for
example, nouveau driver won't work either
To make things easier for btrfs, could it be worthwhile changing the
default page size from 64k back to 4k on default kernels for most
ordinary users?