Using disc spanning for RAID array - eviltoast

I’m planning on building a new home server and was thinking about the possibility to use disc spanning to create matching disk sizes for a RAID array. I have 2x2TB drives and 4x4TB drives.

Comparison with RAID 5

4 x 4 TB drives

  • 1 RAID array
  • 12 TB total

4 x 4 TB drives & 2 x 2 TB drives

  • 2 RAID arrays
  • 14 TB total

5 x 4* TB drives

  • Several 4TB disks and 2 smaller disks spanned to produce a 4 TB block device
  • 16 TB total

I’m not actually planning on actually doing this because this setup will probably have all kinds of problems, however I do wonder, what would those problems be?