Squeezing the maximal possible performance out of Solr / SolrCloud, and Elasticsearch and making them scale well is what we do on a daily basis for our clients. We make sure their servers are optimally configured and maximally utilized. Rafal Kuć gave a long, 75-minute talk on the topic of Scaling Solr with SolrCloud at Lucene Revolution 2013 conference in Dublin. Enjoy!
If you are interesting in working with Solr and/or Elasticsearch, we are looking for good people to join our team.