On 10/07/2010 07:44 PM, Aidan Van Dyk wrote:
> The only case I see a "race to quorum" type of k < N being useful is
> if you're just trying to duplicate data everywhere, but not actually
> querying any of the replicas. I can see that "all queries go to the
> master, but the chances are pretty high the multiple machines are
> going to fail so I want >> multiple replicas" being useful, but I
> *don't* think that's what most people are wanting in their "I want 3
> of 10 servers to ack the commit".
What else do you think they want it for, if not for protection against
data loss?
(Note that the queries don't need to go to the master exclusively if you
can live with some lag - and I think the vast majority of people can.
The zero data loss guarantee holds true in any case, though).
> The difference between good async and sync is only the *guarentee*.
> If you don't need the guarantee, you don't need the synchronous part.
Here we are exactly on the same page again.
Regards
Markus Wanner