One of the biggest challenges when conducting performance testing is to know when you've accomplished your goals. SolrMeter, available at http://code.google.com/p/solrmeter/, makes it very easy to test your Solr configuration. When performance testing Solr, you are typically tweaking configuration values such as cache sizes and query parameters in response to two ongoing activities: the pace of the documents being indexed into Solr, and the pace of the queries being issued to Solr. SolrMeter makes it very easy to control the pace of these two activities through a simple GUI tool. SolrMeter brings together both basic load testing functionality with some visualization and analytics of your Solr instance. A typical example is looking at your cache rates. While you can use the Solr Admin Plugins / Stats page to pull back these results, you are only seeing a snapshot in time.

In the following screenshot, you can see a visualization of the queryResultCache...