Hi,

the attached patch series adds mergerfs, an union file system, and
associated tools mergerfs-tools. I’ve been running it for a while now
and it seems to be stable. Unfortunately I’m not able to mount it in the
system configuration via

(file-system
 (device "/storage/disk*")
 (mount-point "/storage/pool")
 (type "mergerfs")
 (flags '('allow_other, 'use_ino, "moveonenospc=true", "category.create=mfs"))
 (check? #f))

because device is a pattern and not an actual file system path.

Cheers,
Lars