Thank you for the answers. I'm still confused. If fsync is not replicated to the slave, then how is replication affected by a corrupt master? If the master dies and there's a commit recorded in the wal log that didn't actually happen, wouldn't the slave still be expected to be in a sane state, with the wal logs accurately reflecting what's on disk?
Maybe I just don't understand streaming replication enough. The docs seem to say that synchronous commits mean that the slave also has to verify a write before a transaction is considered complete. How does fsync affect the way/order in which statements are sent to the slave for replication? On Thu, Oct 24, 2013 at 9:42 AM, Alban Hertroys <haram...@gmail.com> wrote: > On 24 October 2013 15:04, Fujii Masao <masao.fu...@gmail.com> wrote: > > On Thu, Oct 24, 2013 at 10:39 AM, <maillis...@gmail.com> wrote: > >> Am I wrong? If I'm wrong, is there still danger to the slave > >> in this kind of setup? > > > > No, I think. > > Corruption due to fsync being off on the master will be replicated to > the slave, or - if corruption is bad enough - replication will fail to > replicate affected records entirely. Of course, turning fsync off is > no guarantee for corruption - it's the other way around: having it on > guarantees that you don't get corruption (provided that... etc). > > You could disable replication while fsync is off. I'd verify the data > on the master (by creating a dump, for example) before re-enabling it > again, though. > > -- > If you can't see the forest for the trees, > Cut the trees and you'll see there is no forest. >
