According to Splunk Enterprise Search Performance and Deployment Optimization guidelines, the phone home interval (configured for deployment clients communicating with a Deployment Server) has no impact on search performance.

The phone home mechanism controls how often deployment clients check in with the Deployment Server for configuration updates or new app bundles. This process occurs independently of the search subsystem and does not consume indexer or search head resources that affect query speed, indexing throughput, or search concurrency.

In contrast:

Increasing the number of indexers (Option B) improves search performance by distributing indexing and search workloads across more nodes.

Workload Management (Option C) allows admins to prioritize compute and memory resources for critical searches, optimizing performance under load.

Increasing search heads (Option D) can enhance concurrency and user responsiveness by distributing search scheduling and ad-hoc query workloads.

Therefore, adjusting the phone home interval is strictly an administrative operation and has no measurable effect on Splunk search or indexing performance.

References (Splunk Enterprise Documentation):

• Deployment Server: Managing Phone Home Intervals

• Search Performance Optimization and Resource Management

• Distributed Search Architecture and Scaling Best Practices

• Workload Management Overview – Resource Allocation in Search Operations