7 ms·
Ignore the journal and wal for now (though they certainly contribute to backup complexity). You have a 70GB database file with "apple" near the start and "bana
by tedunangst 4y ago
Ignore the journal and wal for now (though they certainly contribute to backup complexity).
You have a 70GB database file with "apple" near the start and "banana" near the end. You start cp and it copies apple. The application updates apple to "cat", and then banana to "dog". Finally cp copies dog to backup.
You now have a database which contains "apple" and "dog" which never existed at any point in the original timeline.
- jchw 4y agoOK. So CoW snapshotting and other techniques that could take the files at a given point in time would not be subject to this issue? Just to be completely clear. Or, are there other issues?
- mbreese 4y agoI always thought that any file based solution was a risk when copying live databases or file systems. You should always pause writes before your snapshot, but CoW does make this process significantly faster. I’ve never done this with a SQLite database, but I have done it with running VM file systems (with a CoW backend). And the filesystem pause was always very short.