Partitioned cache behavior when insufficient number of nodes are available

Question

I am using Apache Ignite (v2.14.0) in a Kubernetes environment with pods connected over ClusterIP. I am curious about the behaviour of Partitioned caches when number of backups is greater than the number of available nodes.

When I configure caches, let's say I give number of backups as 2, but only start a replicaSet of 2 nodes. What will happen in this case? Will there be only 1 backup on the secondary node or will there still be 3 copies, with 1 node having a local duplicate?

I read up but neither of these pages answered my question:

• https://www.gridgain.com/resources/blog/data-distribution-in-apache-ignite

• https://ignite.apache.org/docs/latest/data-modeling/data-partitioning

• https://ignite.apache.org/docs/latest/data-rebalancing

Answer 1

Only one copy of each partition will be stored per node.

In the provided example where the cluster has 2 nodes and a backup factor is set to 2, the cluster will maintain just 2 copies of each partition (1 primary and 1 backup).