CODEWITHSUNDEEP
cassandra
Southsouth
Southsouth

Reputation: 2695

How does Cassandra balance the load when add a server/node

trying to find articles regarding how Casandra balances the load when add a server/node? that is, after adding a node, how cassandra moves certain partitions from existing nodes to new node, and how quick it could be done?

Upvotes: 1

Views: 182

Answers (1)

Mandraenke
Mandraenke

Reputation: 3266

When you add a node to your existing cluster cassandra automatically will assign token ranges to your new node and stream relevant data to it. While this happens nodetool status will show the node as JOINING.

After streaming completes the node is part of your and will handle requests as any other node also does reducing the load on them. But your data size on the old nodes won't shrink - you need to issue nodetool cleanup to get rid of the now obsolete data.

For how quick this can be done, that depends on your clusters load and data size that must be streamed - but streaming is limited on network bandwidth of course.

Upvotes: 3

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