I am writing 1.2 billion rows of data (two columns) in Cassandra using spark and datastax spark connector. I have a two DC setup, I will be writing with local_quorum. I have 3 replications in both DC. Will there be latency introduced due to other DC. What other things should I keep in mind while inserting Data. I have tested on single DC and results are satisfactory.
1 Answers
Writes will be sent to other DC anyway, but because you're using LOCAL_QUORUM, Spark won't wait for confirmation from nodes in that DC, so it shouldn't affect the latency. The only thing that I would monitor - if the another DC is far away, and/or have a slow link, then the nodes where write happens may start to collect hints, and if this happens, then this may slightly affect performance because hints need to be written & then replayed after the remote node is back.
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