There is a recent thread on this one http://www.mail-archive.com/solr-user@lucene.apache.org/msg40491.html
On Friday 24 September 2010 16:30:36 mike anderson wrote: > What is the right way to upgrade a solr index from Lucene 2.9.1 to 3.x. I'm > getting the exception: > > SEVERE: java.lang.RuntimeException: > org.apache.lucene.index.IndexFormatTooOldException: Format version is not > supported in file '_aw5w.fdx': 1 (needs to be between 2 and 2). This > version of Lucene only supports indexes created with release 3.0 and > later. > > > when I try to start a server with my old index. > > Thanks in advance, > Mike > Markus Jelsma - Technisch Architect - Buyways BV http://www.linkedin.com/in/markus17 050-8536620 / 06-50258350