On Nov 21, 2012, at 11:00 AM, GIROLAMI Philippe <philippe.girol...@cegedim.fr> wrote:
> Hi Mark, > Thanks for the details >>> If the answer is b), what would happen on a 1-replica setup if one commit >>> succeeded and the replica commit failed ? >> What's the reason the commit failed? Either a really bad problem and that >> node will need to be restarted and either won't answer requests or it will >> be asked to recover by the leader when sending it an update that failed. > Something dumb like a full disk for example. So I understand that the leader > for the shard stored to the transaction log which means that if, in the worst > case, it crashes and does not loose disk data, it will replay it. And for > "slaves" crashes, they will get the commit log from the leader. > Is this right ? All of the nodes have their own transaction log. When a node comes back up, he will replay his local transaction log. Then he will contact the leader and compare versions - if he matches, it's all good - if not, he recovers from the leader. If he is the leader, he just replays his own local transaction log. - Mark
