There is specific guidance for rolling upgrades from Solr 8.x to 9.x. Please see here: https://solr.apache.org/guide/solr/latest/upgrade-notes/major-changes-in-solr-9.html#rolling-upgrades
In particular, if you are using Auth and using the PKIAuthenticationPlugin, there are steps you must complete to ensure a smooth upgrade. - Houston On Tue, May 16, 2023 at 9:55 AM Shawn Heisey <[email protected]> wrote: > On 5/16/23 00:25, Saksham Gupta wrote: > > Hi team, We are planning to migrate our solr cloud from solr version8.10 > to > > solr 9. > > 1. Is it okay to plan a rolling upgrade from solr8.10 to 9? > > 2. Is this a major update? If yes, what should be the upgrade procedure? > > I haven't done a major version upgrade of a multi-node cluster before. > I would expect a rolling upgrade to work correctly, and that is the > procedure in the documentation: > > > https://solr.apache.org/guide/solr/latest/deployment-guide/upgrading-a-solr-cluster.html > > One thing to note... if your Solr 8 indexes have EVER been touched by a > Solr version before 8.0, they will not be usable in Solr 9. So if you > upgraded from Solr 7 to Solr 8, you will have to reindex from scratch. > > Thanks, > Shawn >
