Better still put it up on a wiki on https://cwiki.apache.org/confluence/display/ZOOKEEPER/Index
thanks mahadev On Sep 22, 2011, at 1:45 PM, Vishal Kher wrote: > Hi Camille, > > This is very interesting. > > Can you give more info on your setup? > - Network connectivity (bandwidth and latency) that you have between the > data centers? How much of the bandwidth is available for ZK? > - What are the timeout (server and client session timeout) values that you > use? How much latency are the applications willing to tolerate? > > We are thinking of running ZK across data centers as well and it will be > great to see how others are resolving some of these problems. > > Thanks. > -Vishal > > On Thu, Sep 22, 2011 at 11:03 AM, Fournier, Camille F. < > [email protected]> wrote: > >> We spread our ZKs across 3 data centers and in fact, these data centers are >> split across global regions (2 or 4 in one region, one in a remote region). >> To keep throughput up (and note that the throughput you have to worry about >> is only write throughput), we always ensure that the master is in one of the >> "local" data centers. >> >> If you have a very write-heavy and write time sensitive load, this might >> affect your performance. It won't affect reads at all because reads are >> serviced from the memory of the zk you connect to. For a mostly >> read-intensive load, splitting across data centers is unlikely to cause you >> problems. >> >> There is one exception: Monitoring. Even across data centers in the same >> region, we sometimes see zk dashboard unable to properly monitor the leader >> of a heavily-utilized cluster. This is due to the way the 4lw connections >> are managed, and something I'm trying to fix. >> >> If you have the machines to test, I would recommend running zk-smoketest ( >> https://github.com/phunt/zk-smoketest) on the proposed config. >> >> C >> >> -----Original Message----- >> From: Damu R [mailto:[email protected]] >> Sent: Thursday, September 22, 2011 10:50 AM >> To: [email protected] >> Subject: zookeeper cluster spanning datacenters >> >> Hi, >> I would like to know the downsides of having a zookeeper cluster that spans >> multiple datacenters. The requirement is a datacenter failure should not >> bring down the zookeeper cluster. From my understanding it is not possible >> to have a hot/cold cluster kind of setup possible. So we are thinking of >> putting zk servers in 3 colos(1+1+1 or 2+2+3). One of the major drawback I >> could think of is the throughput of the system affected by latency. The >> system does not require high throughput and can accept some latency. How >> much effect will the latency have on the throughput of the system? What are >> the other downsides of spreading the cluster across datacenters? >> >> Regards >> Damu >>
