Solr strives to keep backwards-compatible 1 major revision, so 4.x should be able to work with 3.x indexes. One caution though, well actually two.
1> If you have a master/slave setup, upgrade the _slaves_ first. If you upgrade a master fist and it merges segments, then the slaves won't be able to read the 4.x formst. 2> make backups first <G>... BTW, when the segments are written, they should be written in 4.x format. So I've heard of people doing the migration, then forcing an optimize just to bring all the segments up to the 4.x format. Best Erick On Tue, May 7, 2013 at 3:28 PM, Skand Gupta <skandsgu...@gmail.com> wrote: > We have a fairly large (in the order of 10s of TB) indices built using Solr > 3.5. We are considering migrating to Solr 4.3 and was wondering what the > policy is on maintaining backward compatibility of the indices? Will 4.3 > work with my 3.5 indexes? Because of the large data size, I would ideally > like to move new data to 4.3 and gradually re-index all the 3.5 indices. > > Thanks, > - Skand.
