Hi Feroz, due to Lucene's backward compatibility policy ( http://wiki.apache.org/lucene-java/BackwardsCompatibility ), a Solr 4.1 instance should be able to read an index generated by a Solr 3.5 instance. This would not be true if you need to change the schema. Also, be careful because Solr 4.1 could and will change the index files and will make them unreadable by Solr 3.5 (so you should make a backup in case you need to revert to 3.5 for some reason). This means, that if you can't shutdown your whole application all together, you could update the slaves first, and then the masters. Replacing all servers together will also work.
That said, you should not use 4.1 if you are using Master/Slave, there are some known bugs in that specific feature in 4.1 that were fixed for 4.2. Tomás On Mon, Mar 11, 2013 at 10:56 AM, feroz_kh <feroz.kh2...@gmail.com> wrote: > Hello, > > We are planning to upgrade our solr servers from version 3.5 to 4.1. > We have master slave configuration and the index size is quite big (i.e. > around 14 GB ). > 1. Do we really need to re-format the whole index , when we upgrade to 4.1 > ? > 2. What will be the consequences - if we do not re-format and simply > upgrade > war file and config files ( solrconfig.xml, schema.xml ) on all slaves and > master together. (Shutdown all master & slaves and then upgrade & startup) > ? > 3. If re-formatting is neccessary - then what is the best tool to achieve > it. ( How long does it usually take to re-format the index of size around > 14GB ) ? > > Thanks, > Feroz > > > > > -- > View this message in context: > http://lucene.472066.n3.nabble.com/Upgrade-Solr3-5-to-Solr4-1-Index-Reformat-tp4046391.html > Sent from the Solr - User mailing list archive at Nabble.com. >
