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Cassandra Consistency Light Transactions

I read about Cassandra 2 small transactions. Is the consistency level of such a record always in QUORUM? Does this mean that even if I have the installation of several data centers with 100 nodes, the quorum of the entire cluster is involved (most row replicas in all data centers)? Will it really be slow and won't affect availability?

Can we fulfill the coordination LOCAL_QUORUM or EACH_QUORUM? This would be preferable if data authors replicated in multiple data centers always came from a particular data center.

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The recommended level of consistency for lightweight transactions is SERIAL. However, behind the scenes, SERIAL is worse than QUORUM because it is multiphase QUORUM. As you said, the situation may become more complicated if you have several DC-Datastax, evaluating "degradation is effective to one third of normal . "

There is LOCAL_SERIAL, which may be ideal for your situation when all domain controllers receive data from a specific DC current.

Here you can find additional information:

LIGHT OPERATIONS
LINEARIZATION CONSULTATION

NTN, Carlo

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In fact, the quorum will be just over half the replication ratio of your cluster. In practice, replication rates are usually kept low (3 or 5) to avoid wasting space.

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Source: https://habr.com/ru/post/972928/

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