> cluster name for both machines. So in other words, if we want to launch two > separate instances of cassandra and keep them separate, we must make sure > each uses a different cluster name or else they will gang up into the same > cluster? But how do they even discover each other? Can someone enlighten > me please? Thanks.
It is highly recommended to use distinct cluster names, in particular because it can help avoid accidentally "merging" two independent clusters. As for how it happened: There is no magic discovery going on that would pick IP:s at random, but one could certainly e.g. accidentally configure the seed node on one to point to the other or some such. (1) does nodetool -h localhost ring show an unexpected node? (2) i'd suggest checking system.log on each node for the first appearance (if any) of the "unexpected" ip address and correlate (by time) with what happened on the other node (was it restarted at the time for example, potentially wth a bad conf?) (3) are these two single-instance cassandras that have never participated in another cluster? -- / Peter Schuller (@scode on twitter)
