On Wed, Jun 18, 2008 at 11:24:16PM +0800, Craig Ringer wrote:
> Alan Hodgson wrote:
> >You can't just backup a live database from the filesystem level and expect
> >it to work ...
>
> It should be OK, if less than ideal, if:
>
> - You have fsync enabled (which you do if you care about your data);
I've always wondered about this! Isn't fsync only a side-effect of
having a write-back cache between programs and the disk? This means
it's only purpose is to ensure that the cache is consistent with what's
on disk. Because all programs running within a system are running on
top of the cache they don't know or care whether the cache actually
matches up to the disk.
Therefore, if I understand things correctly, the state of fsync
shouldn't matter in this use case. It's equally borken independent to
the state of fsync.
Sam
