I have Solr 4.6 installed on my machines, and have multiple cores each of size more than 500G's. The problem with solr 4.6 is that the sharding is very unstable. So I want to migrate my cores from solr 4.6 to solr 4.10 without providing any downtime to my customers. Reindexing the cores will take a long time and a lot of resources. If anyone can suggest some solution(list of steps to follow) for this, it will be very helpful.
Thanx in advance.
You shouldn't need to reindex if staying on the same major version of solr. Presumably you will have a parallel Solr infra for 4.10. If you can stop your solr you can just copy the data directories over. Otherwise you can do a hot backup (i.e. while still having index open) using the ReplicationHandler to copy Solr's data directory elsewhere on the local system. Then do whatever you like with that directory. You can launch the backup whenever you want by going to a URL like this:
http://host:8080/solr/replication?command=backup&location=/tmp/backup
More details can be found here:
http://wiki.apache.org/solr/SolrReplication
I would do an optimize on your index either before or after backup via the admin front end.
