I got one of the way to do it. I can install solr on a separate server & use solrj apis within alfresco for integration.
Programatically, i can dump alfresco content for indexing to solr search using solrj using custom built xml for alfresco contents. Once xml are available to solr, it can be consumed by solr server & can be indexed by it. These indexes would be separate from alfresco OOTB indexes.
Once indexed, it is good to go. Using solr apis, i can search same content in solr server, instead of alfresco plus benefit of integrating multiple content sources with solr so that solr can be used as universal search.
However, when content items go to large volumes, i could see a performance hit as for every content item in alfresco , solr needs to index it. Any workaround possible?
Regards.