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
