How can I change index size in cluster ?

[mima_splunk]

Hello
I wanted to increase the size of the index. My indexes are configured on multiple machines in a cluster. Where can I change size of this index ? When I tried to change it on one of the machines I received a message : Encountered the following error while trying to update: In handler 'indexes': invalid action for clustering slave.
Please help.
Thx

[ChrisG]

You need to deploy the changes to indexes.conf as part of a configuration bundle. See Configure the peer nodes in the Managing Indexers and Clusters manual, and then Update common peer configurations.