UFS Raid 1 support

[Ericloewe]

Not exactly, though I did evaluate it and find it's performance to be inadequate. What I'm referring to is the way it uses a single, dedicated parity drive, regardless of the number of data drives. That has value if a drive fails completely, but consider what it means when it finds data that doesn't match parity in the unRAID equivalent of a ZFS scrub. It has to decide whether the parity is correct or the data on the drive is correct, but there's absolutely no way of knowing. The solution adopted by unRAID is always to assume that the data on the drive is correct, and to update the parity accordingly. In other words, there is absolutely no protection against bit rot.

Damn, that's asinine. I guess corners just have to be cut, but would a checksum really hurt them that much...?

 

[Robert Trevellyan]

I guess corners just have to be cut...

Let's not forget that it's a paid product if you want to use more than 3 devices.

 

[Ericloewe]

Let's not forget that it's a paid product if you want to use more than 3 devices.

Who in their right minds pays for something that sounds like it's meant to make something vaguely useful out of random drives? That's beyond crazy.

Of course, I meant cutting corners to fit in a certain hardware budget. But anyone paying for something should go with a proper solution.

 

[danb35]

I wasn't especially intending to debate the merits of unRAID (especially since I've never used it and wasn't recommending it), but what they're doing sounds rather similar to RAID 4, right?

Based solely on their claims (again, I've never used the product), unRAID allows you to assemble a collection of random-size drives, use the largest one for parity, and then give you ~full capacity of the remaining disks. You can expand your volume capacity at any time by adding disks, one or more at a time. It gives you enough redundancy to recover from a single disk failure. unRAID 6 supports btrfs, which does provide checksumming of data and should be comparable to ZFS in protecting from bit-rot--and even if it didn't, nothing else but ZFS does either. I don't see how unRAID's implementation is worse than any other legacy RAID4 or RAID5 solution, and it may be better than some.

In short, unRAID's features seem to fit a pretty significant need/want. We can say all we want that FreeNAS and ZFS are better, but can't we agree that, at least for home use, it'd be awfully nice to be able to safely expand our pools a disk at a time?

 

[Ericloewe]

, but can't we agree that, at least for home use, it'd be awfully nice to be able to safely expand our pools a disk at a time?

Yeah. It's not a dealbreaker for me (obviously), but it's a nice-to-have. At the very least, it'd expand the user base and reduce noise on the forum.

 

[Robert Trevellyan]

unRAID's features seem to fit a pretty significant need/want

I won't argue with this, and their support of Docker &c is way cool, but their approach to data protection is ... less robust than what I'm looking for. Yes, they're talking about BTRFS these days too, but my confidence in ZFS is way higher than my confidence in BTRFS.

Sorry for veering off-topic.