Splunk Enterprise

Setting useACK in outputs.conf in a Distributed Environment (Universal Forwarder + Heavy Forwarder + Indexer)

edoardo_vicendo
Builder

Hello,

In a distributed environment with Universal Forwarder, Heavy Forwarder and Indexers, like this one:

UF --> HF --> IDX

How do you set useACK=true in outputs.conf ?

Is it needed to be enabled both on Universal Forwarder and Heavy Forwarder?

We currently have it enabled only on the Heavy Forwarder.

Thanks a lot,

Edoardo

Labels (2)
0 Karma
1 Solution

richgalloway
SplunkTrust
SplunkTrust

As I understand it, the instance with useACK=true will buffer packets until they are acknowledged by the indexer.  If useACK=false then the packet is discarded once it is sent.  (These are Splunk packets, not TCP packets.)  Also, useACK adds a kind of flow control to the data stream.  For better end-to-end control, use useACK=true on the UF and HF.  Note that this will force the instance to use more memory.

---
If this reply helps you, Karma would be appreciated.

View solution in original post

richgalloway
SplunkTrust
SplunkTrust

As I understand it, the instance with useACK=true will buffer packets until they are acknowledged by the indexer.  If useACK=false then the packet is discarded once it is sent.  (These are Splunk packets, not TCP packets.)  Also, useACK adds a kind of flow control to the data stream.  For better end-to-end control, use useACK=true on the UF and HF.  Note that this will force the instance to use more memory.

---
If this reply helps you, Karma would be appreciated.

edoardo_vicendo
Builder
0 Karma
Get Updates on the Splunk Community!

Splunk Observability Cloud’s AI Assistant in Action Series: Analyzing and ...

This is the second post in our Splunk Observability Cloud’s AI Assistant in Action series, in which we look at ...

Elevate Your Organization with Splunk’s Next Platform Evolution

 Thursday, July 10, 2025  |  11AM PDT / 2PM EDT Whether you're managing complex deployments or looking to ...

Splunk Answers Content Calendar, June Edition

Get ready for this week’s post dedicated to Splunk Dashboards! We're celebrating the power of community by ...