# Cassandra
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## Cassandra: Replication
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* RF = Replication Factor (how many times each piece of data is replicated)
* CL = Consistency Level (ONE, QUORUM, ALL) (How many reads or writes need to happen before we consider the read or write "done")
* ONE= 1 machine
* QUORUM = majority of the RF machines
* ALL = all of the RF machines



## Cassandra: Resources
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* [DS220 Data Modeling](https://academy.datastax.com/resources/ds220-data-modeling)





