Setting the Number of Replicas

In a multi-node cluster, you must ensure that the replica values are set correctly. You use the Search Options page to set the replica values.

On the Search Options page, when you specify a replica value, the replica value is applicable to a search instance and to the security index. Consider the following before you specify a replica value.

See Managing General Search Options.

• Ensure that the replica value is set to 1 or greater than 1 so that in the event of a node failure data loss does not happen. The maximum number of nodes that can be down without loss of data will be equal to the number of replicas (replica count should be less than or equal to N-1), where N refers to the number of nodes in a cluster. Ensure that you set the replica value in all the nodes of a cluster.

  Warning! Oracle PeopleSoft recommends that you do not set the replica value to 0.

• You may set the replica value to greater than 1 if you have more nodes available. For example, if you have 4 nodes in a cluster, and you want to provide high availability even if two nodes fail, then you need to set the replica value to 2.

If the replica value for an index is greater than N-1 (where N is the number of nodes in the cluster), you may find that the status of the cluster as yellow indicating a warning that at least one replica is missing.

For a description of color codes for cluster status, see Viewing the Elasticsearch Cluster Dashboard.