I have used ext4 on LVM (on luks) successfully for many years, more than a decade by now. Never failed on me, expect for the (rather harmless) occasional case of a snapshot becoming unusable if there was too much movement and I didn't make it large enough to start with.

But then, all I use those snapshots for are consistent backups. So I might not count as a snapshot power user.

I occasionally resize busy (mounted) volumes on the fly, also without problems.

@treuss @Natanox
@idlestate