I want to upgrade my NAS to 8x 4TB + 4x 2TB drives and wonder if Btrfs can deal with drives of different sizes and still provide reduncancy.
If one drive fails I do not want to loose my data!
So does Btrfs support
- RAID5 with different sized drives or
- Pooling with Parity?
Actually I prefer the latter one, since when 2 drives fail I could still access the remaining ones.
(Additionally I would like to know if it will be reasonable to upgrade from Ubuntu 16.04.4 LTS to Ubuntu 18.04 for having some newer Btrfs version)
Best Answer
Yes, Btrfs can deal with drives of different sizes and provide redundancy, how the disks are being used then depends on the RAID level being used. For more detailed information, please use the btrfs space allocator calculator here: http://carfax.org.uk/btrfs-usage/
For the other two questions please look at the official status page here:
https://btrfs.wiki.kernel.org/index.php/Status
RAID5/6 is currently officially marked as unstable; it can and will eat your valuable data.
It does support parity, but there is no triple parity - again not yet production ready according to the official wiki.
If you really want/need a COW file system with such features other than RAID0 or RAID1, you should probably take a look at ZFS.