It should focus on easily recoverable data. This means that if I take any drive from the pool and mount it some place else, I would be able to read data from it. Also, if a drive from the pool fails, only data from that drive will be lost. Data from other drives would be unaffected.
I have already tried LVM. I lost a drive in the pool and was able to recover files from the other disks. However, not all of the recovered files were good. Some are too short/corrupted.
Which is why I'm looking for an alternative to LVM. Ideally, the solution would sit on top ext4-formatted disks (or any other filesystem), and drives will fill one by one. And if I want to share my drives (using NFS or Samba), I would just point it to the solution mount.