> 2 - No, metadata robustness absolutely varies across filesystems.

That's misunderstanding the subthread. The upthread point was about metadata atomicity in snapshots, not hardware corruption recovery. A filesystem like ZFS can make sure the journal is checkpointed atomically with the CoW snapshot moment, where dm obviously can't. And I pointed out this wasn't actually helpful because this is a problem that has to be solved above the filesystem, in databases and apps, because it's isomorphic to power loss (something that the filesystem can't prevent).

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nh2 18 hours ago | parent [-]

I believe it is helpful because you can stop an app (such as a DB), FS-snapshot, and then e.g. rsync the snapshot or use any other file based backup tool, and this snapshot is fast and will be correct.

Doing the same with a block device snapshot is not so easy.

	▲	ajross 4 hours ago \| parent [-]
		Again, if your system is "incorrect" having been stopped and snapshotted like that, it is also unsafe vs. power loss, something ZFS cannot save you from. Power loss events are vastly more common than poorly checkpointed database[1] events. [1] FWIW: every database worth being called a "database" has some level of robust journaling with checkpoints internally. I honestly don't know what software you're talking about specifically except to say that you're likely using it wrong.