Availability zones are analogous to racks not data centres . EC2 regions are equivalent to data centres.
You can use vnodes if you want to deploy a cluster across multiple regions (data centres) with one availability zone per region. Each region maintains a separate ring. I don't know if you can use vnodes on multiple rack topologies however. In my case, Wlwe host a EC2 cluster with 2 fold replication and 2 zones in the same region and we don't use vnodes On Dec 5, 2013 2:32 PM, "Andrey Ilinykh" <ailin...@gmail.com> wrote: > Hello everybody! > We run cassandra 1.1 on ec2 instances. We use three availability zones, > the replication factor is 3 also. NetworkTopologyStrategy guarantees each > row is replicated in all availability zones. So, if we lost one zone quorum > operations still work. We think about to upgrade to 1.2. Virtual nodes are > the main reason. My understanding is - vnodes are distributed randomly, so > their is no way to put every row into all availability zones. Am I right? > What would be the best way to deploy vnodes across several data centers > (availability zones)? > > > Thank you, > Andrey >
