Hi, I'm currently looking at Cassandra in the context of Disaster Recovery. I have 2 Data Centres, one is the Primary and the other acts as a Standby. There is a Cassandra cluster in each Data Centre. For the time being I'm running Cassandra 2.0.9. Unfortunately, due to the nature of my data, the consistency levels that I would get out of LOCAL_QUORUM writes followed by asynchronous replication to the secondary data centre are insufficient. In the event of a failure, it is acceptable to lose some data, but I need Casual Consistency to be maintained. Since I don't have the luxury of performing nodetool repairs after Godzilla steps on my primary data centre, I use more strictly ordered means of transporting events between the Data Centres (Kafka for anyone who cares about that detail).
What I'm not sure about, is how to go about copying all the data in one Cassandra cluster to a new cluster, either to bring up a new Standby Data Centre or as part of failing back to the Primary after I pick up the pieces. I'm thinking that I should either: 1. Do a snapshot ( https://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_backup_takes_snapshot_t.html), and then restore that snapshot on my new cluster ( https://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_snapshot_restore_new_cluster.html ) 2. Join the new data centre to the existing cluster ( https://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_add_dc_to_cluster_t.html). Then separate the two data centres into two individual clusters by doing . . . something??? Does anyone have any advice about how to tackle this problem? Many thanks, -Phil
