Point releases,7.0 to 7.1, are normally in place upgrades one node at a time. The cluster will remain online at all times.
AFAIK major version upgrades would normally allow for in place upgrade, supporting a mixed environment during the change over. If the on disk format changed there may be a migration process or the node may need to be drained, and then bought back into the cluster. 0.6 to 0.7 did not allow for a mixed environment due to some inter node communication changes. These were discussed well before even the first beta. But I'm guessing, who knows that the future will bring. In general though, cassandra is in use in large production systems and any upgrade plan will take this into consideration. Aaron On 2 Dec 2010, at 14:50, Nick Santini wrote: > Hi, > this is an hypothetical situation highly likely to happen: > > I have a cassandra 0.7 cluster, filled with production data, and I want to > upgrade cassandra to the 0.8 version (and so on as new versions get released) > > what happen with my data and keyspace / column families definitions? whats > the process to upgrade cassandra in a production cluster? > > > Thahks > > > Nicolas Santini
