Sharding across dissimilar sized drives >2 drives

[plattrap]

Instead of just mirroring, could you spread writes across multiple drives?

e.g.

sorted_mounts = sort_mounts_by_free_precentage()
for mount in sorted_mounts
  handle = PLACEHOLDER
  if index < number_of_copies
    handle = write_data(mount)
  write_metadata(mount, handle)

[s-d-adams]

I think the changes that would be needed to make this work would be far too complex to justify the benefits.

As an approximation to this you could take the smaller of the drives and combine them using softraid(4) with the CONCAT discipline, then combine that RAID filesystem with the one from the larger drive using muxfs.