Which Cassandra version should I use (2018)?

If you’re starting new or in the 3.0.x series: 3.11.2

• Apache Cassandra 3.0 is supported until 6 months after 4.0 release (date TBD)

If you’re in 2.x, update to the latest in the series (2.1.20, 2.2.12)

• Apache Cassandra 2.2 is supported until 4.0 release (date TBD)
• Apache Cassandra 2.1 is supported until 4.0 release (date TBD). Critical fixes only

Long version

– If you’re starting new or in the 3.0.x series: 3.11.2

Stability wise, both 3.0.16 and 3.11.2 are stable at this point. The biggest advantage of 3.11.2 vs 3.0.16 is the additional features that went into the 3.x series (with x>0).
Not all features are desirable though. (Move away from Materialized Views, since they are marked as experimental on the latest releases).

Despite this, the Slow Query Log and Change-Data-Capture are examples of really useful ones that might make you consider jump to 3.11.2, as you will not get them in the 3.0.x series. JBOD users should also look at CASSANDRA-6696 might be interesting.

– If you’re in 2.x, update to the latest in the series (2.1.20, 2.2.12)

As you might expect, these two releases are very stable, since they have a lot of development time on top of them. If a cluster is still running these Cassandra versions, the best is to upgrade to
the latest releases in the respective series (either 2.1.20 or 2.2.12).

To me, the biggest downside of using these versions, it the fact that they will probably be the last releases of either Cassandra series. The support for critical bugs is here until 4.0 is released (https://cassandra.apache.org/download/) but besides that no major changes or improvements will come.

An additional possible thing to consider, that if there may not be a direct upgrade to the 4.x series, an upgrade may need to be done via 2.x -> 3.x -> 4.x.

But for now, I would stick with the recommendation keep your current major version if you’re already there and not needing anything new!

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