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igor.rmarinho_185445 avatar image
igor.rmarinho_185445 asked ·

Is it possible to separate a DC for DR testing then rejoin it to the cluster post-testing?

Hello everyone!

I have 2 datacenters DC1(3 nodes) and DC2(one node) and I want to convert datacenter 2 in a stand alone, it's been used as a DR, so it would keep the data and use it separately from dc1 during a test, and after I finish it re-joint DC2 to DC1 as it was at the beginning. Is it possible?

Thank you.

cassandraclusterdr
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@igor.rmarinho_185445 I'll respond to your first question. Since it's unrelated, please do a separate post for this question. Cheers!

If I have DC1 (3 nodes) using LOCAL_QUORUM should I use LOCAL_QUORUM in my DC2 that has only one node? Or Should I use LOCAL_ONE ?


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1 Answer

Erick Ramirez avatar image
Erick Ramirez answered ·

@igor.rmarinho_185445 The quick answer is no, it is not possible to make a DC that is part of a cluster a standalone cluster of its own. You will need to go through a decommission process to achieve that otherwise the nodes remaining in the cluster will be storing hints for the DC and put pressure on your existing cluster.

Administrators with a lot of expertise in Cassandra would be able to workaround it but there is a lot of room for human error and it is not advisable. We recommend you build a separate cluster specifically for testing purposes and populate it with data from your cluster snapshots. Cheers!

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Thanks Erick, I saw this post on DataStax, but I was hopping to do it in a easier way, but the token range thing block it the usually create structure and restore data from snapshot.

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Erick Ramirez avatar image Erick Ramirez ♦♦ igor.rmarinho_185445 ·

If your DC2 only has one node, you can simply copy the snapshots from that one node to the new node using the "refresh method". Cheers!

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