Complex Solr faceting
Complex Solr faceting « Raspberry blog
# How to create multiple facets on the same field by using a key for a unique name and the exclusion of tagged filterqueries for different counts
# How to use the multiple facet count results to render a single interface element

Scaling Lucene and Solr
Scaling Lucene and Solr | Lucid Imagination
While many Lucene/Solr applications will never outgrow a single,
well-configured machine, the fact is, more and more applications are
pushing beyond the single machine limit due to either index size or
query volume. In discussing Lucene and Solr best practices for
performance and scaling, Mark Miller explains how to get the most out
of a single machine, as well as how to harness multiple machines to
handle large indexes, large query volume, or both.

Indexing JSON in Solr 3.1
Lucid Imagination » Indexing JSON in Solr 3.1
Solr has been able to produce JSON results for a long time, by adding wt=json to any query. A new capability has recently been added to allow indexing in JSON, as well as issuing other update commands such as deletes and commits.

All of the functionality that was available through XML update commands can now be given in JSON.