Apparently this feature does not exist so I copy the same mail I sent to "user". What are your opinions on creating a Jira issue requesting this new feature:
With SolrDeletionPolicy you can chose the number of "versions" of the index to store ( maxCommitsToKeep, it defaults to 1). Well, how can you revert to an arbitrary version that you have stored? Is there anything in Solr or in Lucene to pick the version of the index to load? The idea rose from a discussion with some fellows about "really paranoid users" that want to keep several backup versions of the index and pick one that worked in the past (after the index was corrupted in some way, probably not immediately noticeable, and not having the possibility to re index the data) Thank you Emmanuel
