Migrate Datastax Enterprise Cassandra to Apache Cassandra

Question

We have currently using DSE 4.8 and 5.12. we want to migrate to apache cassandra.since we don't use spark or search thought save some bucks moving to apache. can this be achieved without down time. i see sstableloader works other way. can any one share me the steps to follow to migrate from dse to apache cassandra. something like this from dse to apache. https://support.datastax.com/hc/en-us/articles/204226209-Clarification-for-the-use-of-SSTABLELOADER

Answer 1

1. Figure out what version of Apache Cassandra is being run by DSE. Based on the DSE documentation DSE 4.8.14 is using Apache Cassandra 2.1 and DSE 5.1 is using Apache Cassandra 3.11

2. Simplest way to do this is to build another DC (Logical DC per Cassandra) and add it to the existing cluster.

3. As usual, with a "Nodetool Rebuild {from-old-DC}" on to the new DC nodes, let Cassandra take care of streaming data to the new Apache Cassandra nodes naturally.

4. Once data streaming is completed, based on the LoadBalancingPolicy being used by applications, switch their local_dc to DC2 (the new DC). Once the new DC starts taking traffic, shutdown nodes in old DC say DC1 one by one.

Answer 2

1. alter keyspace dse_system and dse_security not using everywhere
2. on non-seed nodes, cleanup cassandra data directory
3. turn on replace in cassandra-env.sh
4. start instance
5. monitoring streaming process using command 'nodetool netstats|grep Receiving'
6. change seeds node definition and rolling restart before finally migrate previous seeds nodes.