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Cars require regular maintenance and have known failure modes if you don't bother to do it its neither magical nor dangerous. Snapraid + ext4 doesn't particular

Cars require regular maintenance and have known failure modes if you don't bother to do it its neither magical nor dangerous. Snapraid + ext4 doesn't particularly simpler than zfs just different. The fundamental tradeoff of space vs reliability seems to be mathematically tied. It's impossible to do better in one dimension without sacrificing the other. Making it possible to lose SOME of your data in fact seems to be the worst choice. ZFS makes it trivial to lose nothing. Use enough hardware and do cheap replication regularly and scrub periodically. If anything the fact that snapraid by not live replicating every change to every disk in the array makes it impossible to achieve the reliability offered by ZFS. It's forever the inferior cousin and in fact more complicated for layering a dissimilar technology on top of the other.

imiric 4y ago
SnapRAID has its drawbacks, sure. As with any technology, deciding to use one solution over another is a balancing act of choosing the set of drawbacks that are acceptable for a particular use case. In this case, _for my simple needs_ of running a home NAS, the fact SnapRAID doesn't run in real-time is not an issue. In fact, I prefer being in control of when it runs, and what it's doing exactly. Having a short time window where some new data is not replicated is a negligible drawback to me. OTOH, while ZFS solves this particular issue, its drawbacks of being difficult to scale, and a huge black box that claims to "just work", when in fact my _entire_ array relies on it working perfectly, 100% of the time, are a tough pill to swallow. I'm sure that with the years of dedicated improvements and stability fixes, it's a battle-tested system where the likelihood of it failing is close to 0, even on Linux. But the fact that it's theoretically possible is a deal-breaker to me. In this sense, I much prefer SnapRAID's approach that makes this literally impossible. SnapRAID could stop working entirely or disappear tomorrow, and all my data is perfectly safe. So, yes, SnapRAID + ext4 is radically simpler than ZFS, IMO. Would I recommend this setup in a corporate environment, where company resources are on the line? Probably not. But I would still advocate against ZFS and mdadm, and probably suggest something like Ceph instead.

imiric 4y ago

SnapRAID has its drawbacks, sure. As with any technology, deciding to use one solution over another is a balancing act of choosing the set of drawbacks that are acceptable for a particular use case. In this case, _for my simple needs_ of running a home NAS, the fact SnapRAID doesn't run in real-time is not an issue. In fact, I prefer being in control of when it runs, and what it's doing exactly. Having a short time window where some new data is not replicated is a negligible drawback to me. OTOH, while ZFS solves this particular issue, its drawbacks of being difficult to scale, and a huge black box that claims to "just work", when in fact my _entire_ array relies on it working perfectly, 100% of the time, are a tough pill to swallow. I'm sure that with the years of dedicated improvements and stability fixes, it's a battle-tested system where the likelihood of it failing is close to 0, even on Linux. But the fact that it's theoretically possible is a deal-breaker to me. In this sense, I much prefer SnapRAID's approach that makes this literally impossible. SnapRAID could stop working entirely or disappear tomorrow, and all my data is perfectly safe. So, yes, SnapRAID + ext4 is radically simpler than ZFS, IMO. Would I recommend this setup in a corporate environment, where company resources are on the line? Probably not. But I would still advocate against ZFS and mdadm, and probably suggest something like Ceph instead.