Where does the burden fall on a search?

[mjj47]

I have an enterprise system composed of 6 search heads and 8 indexers. I am trying to look at current cpu loads to tell how well my current system is set up. When I issue a search, which machine is doing the heavy lifting? indexers, or search head? I'm just curious as to how splunk does searching. Thanks.

[grijhwani]

The search head merely aggregates and formats for presentation the results it gets back from distributed queries to the indexers. The indexers do all the hard work of index searching and collating, which is heavy on IO, and moderately heavy on CPU. Search head load is pretty trivial in comparison.