I'd go with 6.6. Technically you do not have to re-index, although if you can it's preferable. Solr (well, mostly Lucene) will allow reading "one major version back", so any 6x Solr should work fine with a 5x index. As the segments get merged, they'll be brought up to the 6x format. There's also the Lucene IndexUpgrader process that can be run to upgrade your index.
If you're doing bulk indexing, you may want to consider indexing from a SolrJ client, see: https://lucidworks.com/2012/02/14/indexing-with-solrj/ Best, Erick On Mon, Aug 7, 2017 at 8:20 AM, Hari Baskar <contacthar...@yahoo.com.invalid> wrote: > Hi, > We are currently running Solr 5.1 in production. We do not use SolrCloud > now . We plan to move to 6.x and use SolrCloud. Any specific recommendations > on the recommended Solr 6.x version to use in prod. We are open to reindex > all the collections during this migration. Outr major use is full text > search. We use data import handler with SQLEntityProcessor and Apache tika to > index documents. > -Hari
