Anti-entropy repairs are known to be a very peculiar maintenance operation of Cassandra clusters. They are problematic mostly because of the potential of having negative impact on the cluster's performance. Another problematic aspect is the difficulty of managing the repairs of Cassandra clusters in a careful way that would prevent the negative performance impact.
Based on the long-term pain we have been experiencing with managing repairs of nearly 100 Cassandra clusters, and being unable to find a solution that would meet our needs, we went ahead and developed an open-source tool, named Cassandra Reaper , for easy management of Cassandra repairs.
Cassandra Reaper is a tool that automates the management of anti-entropy repairs of Cassandra clusters in a rather smart, efficient and careful manner while requiring minimal Cassandra expertise.
I will have to cover some basics of eventual consistency mechanisms of Cassandra, after which I will be able to focus on the features of Cassandra Reaper and our six months of experience having the tool managing the repairs of our production clusters.