Answer
Batch Processor is deployed as part of ifsapp-int.ear, which runs in the Integration cluster — a lighter version is also deployed as part of ifsapp-main.ear in the main cluster, but the full Batch Processor capacity lives in the Integration cluster specifically. To scale Batch Processor throughput, extend the Integration cluster rather than the main application cluster — this is the key architectural fact to know before attempting any cluster-extension work, since scaling the wrong cluster won't actually add Batch Processor capacity.