Alain,
AFAIK, the DC replication is not linearizable. That is, writes are are not replicated according to a binlog or similar like MySQL. They are replicated concurrently. To answer you questions: 1 - Replication lag in Cassandra terms is probably “Hinted handoff”. You’d want to check the status of that. 2 - `nodetool status` is your friend. It will tell you whether the cluster considers other nodes reachable or not. Run it on a node in the datacenter that you’d like to test connectivity from. Cheers, Jens ——— Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin Twitter On Fri, Dec 19, 2014 at 11:16 AM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > Hi guys, > We expanded our cluster to a multiple DC configuration. > Now I am wondering if there is any way to know: > 1 - The replication lag between these 2 DC (Opscenter, nodetool, other ?) > 2 - Make sure that sync is ok at any time > I guess big companies running Cassandra are interested in these kind of > info, so I think something exist but I am not aware of it. > Any other important information or advice you can give me about best > practices or tricks while running a multi DC (cross regions US <-> EU) is > welcome of course ! > cheers, > Alain
