I need to set up a Cassandra cluster with 3 nodes and RF=1. I want to set up a cron job, that runs node tool repairs once a week, on all three nodes at the same time. Will this affect the data that is being sent to the cluster while the node tool repair is going on? Will the node under going nodetool repair able to serve the new requests?
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What nodetool repair does is it compares the data between all the holders of the data piece and resolves inconsistencies.
With RF=1 means you only store one copy of data = no reserve copies = nothing to compare with = repair operation with RF=1 does nothing.
single-node repair is special cased to be a no-op. (c) CASSANDRA-1691
I recommend you to keep RF=3 (2 proved to be difficult to manage in some cases, e.g. to support losing nodes + being available, 3 allows you to have consistent view on data + lose 1 node)
