Building a Search role

The Building a Search role is only relevant if you are using a search provider that can be hosted on a separate server, such as Solr or Coveo. If you are using Lucene as your search solution, then you will need to either index on every front-end server, or index on one server and copy that index to the rest.

If you are using a search solution such as Solr, you have greater flexibility because the search engine can be centralized on the network, and data can be indexed once and available everywhere. It is strongly recommended that you use Solr in all production scenarios, and try to use Lucene for development only. Indexing is a very CPU intensive process that could affect the performance of your CM servers. If your search indexing is a long running process, you should consider setting up a separate Sitecore instance used solely for indexing

The steps for setting up Solr 4.9 are located at: https://archive.apache.org/dist/lucene/solr/ref-guide/apache-solr-ref-guide-4.9.pdf

The Sitecore documentation for setting up Solr is located here. 

The config files required to set up Solr are located at:

https://dev.sitecore.net/Downloads/Sitecore_Experience_Platform/8_0.aspx