Huang, AFAIK, the write sync process in your example is:
1. Client connect to a follower and send update request; 2. The follower redirects the request to leader (it doesn't persist the state on disk yet!); 3. The leader atomically broadcast the requests, in order, to all followers; 4. Each follower receives the proposal, write it to disk (including the one the client is connected to), and, if successful on writing, sends an acknowledgement (ACK) message to the leader; 5. When the leader receives the ACK from majority of followers it broadcasts a COMMIT message and deliver the message locally. 6. Each follower will deliver the message when they receive the COMMIT from leader; 7. The follower in step 1 then notifies the client. That is, all writing is routed through the leader, but reads go locally to each follower. Edward On Fri, Sep 6, 2013 at 4:14 AM, ch huang <[email protected]> wrote: > zookeeper use zad not paxos ,so here is discuss zad :) > > On Fri, Sep 6, 2013 at 2:29 PM, Flavio Junqueira <[email protected] > >wrote: > > > Did you mean to say zab instead of paxos? > > > > -Flavio > > > > On Sep 6, 2013, at 6:11 AM, Martin Kou <[email protected]> wrote: > > > > > The follower doesn't persist in the beginning - not until it's sure it > > had the consensus of the quorum. Also, the client only talks to the node > it > > is connected to. > > > > > > The general algorithm you're looking for here is Paxos. You may want to > > look that up. > > > > > > Sent from my iPhone > > > > > >> On Sep 3, 2013, at 11:54 PM, ch huang <[email protected]> wrote: > > >> > > >> hi,all: > > >> i am very confused about the write sync process,what i thank > is > > >> ,client connect to one of follower ,send a update request to it,and > the > > >> follower persisted the update to it's disk ,then forward this request > to > > >> the leader,the leader broadcast it to all it's follower, if the leader > > get > > >> responce of the majority of all follower say the update succeed, it > > commits > > >> the update ,and the client will get success response (from who? the > > leader > > >> or the follower who connected?) > > >> > > >> so before leader persisted the change ,this change should be persisted > > on > > >> majority of followers ? > > >> > > >> what i think is right?? > > > > >
