I don't know what your basis of measurement is, so I'll continue to ignore your ratios. Tolerance of crash consistent state isn't exclusive to databases. Filesystems themselves are often designed to tolerate, for example, sudden power loss without corruption. Applications that manage large collections of files can also achieve this; maildir is an example of such a scheme. All of these systems are using related principles of consistency, and all of them can be correctly backed up by copying volume snapshots.
are you ignoring the main point too, or simply missing it entirely (repeatedly)?
the fact there exist some applications (databases, applications using maildir) that correctly use write barriers doesn't mean all applications are always consistent on disk
Comments
I don't know what your basis of measurement is, so I'll continue to ignore your ratios. Tolerance of crash consistent state isn't exclusive to databases. Filesystems themselves are often designed to tolerate, for example, sudden power loss without corruption. Applications that manage large collections of files can also achieve this; maildir is an example of such a scheme. All of these systems are using related principles of consistency, and all of them can be correctly backed up by copying volume snapshots.
are you ignoring the main point too, or simply missing it entirely (repeatedly)?
the fact there exist some applications (databases, applications using maildir) that correctly use write barriers doesn't mean all applications are always consistent on disk