On Thu, Jun 25, 2009 at 10:10 AM, Harold Lim<[email protected]> wrote: > > Hi, > > Is the replication factor configurable? For example, Can I configure the > replication factor per column-family (e.g., 5 for column-family a and 3 for > column-family b).
It is currently only configurable globally. It may make sense to configure on a table/namespace basis. IMO it does not make sense on a CF basis. > Also, I am interested about the replication details. Sandeep wrote: > "When there's a failure and the #of replicas for a given key goes down, > Cassandra does not aggressively create a new copy for the data. The > assumption is that the failed node will be replaced soon enough, and work > can continue with the other 2 replicas." > > When and how does cassandra replicate when the replication count of a > particular data goes below the replication factor? How does it monitor the > replication count of a particular data? Currently it re-replicates (repairs) lazily. This is called "read repair" and we follow essentially the model given in the Dynamo paper. Non-lazy repair is being worked on at https://issues.apache.org/jira/browse/CASSANDRA-193 -Jonathan
