Hi Attila, Minor version upgrades are generally fine to do in-place, unless otherwise specified on NEWS.txt < https://github.com/apache/cassandra/blob/cassandra-4.0.1/NEWS.txt> for the specific versions you're upgrading. Cassandra is designed with this goal in mind, and potentially disruptive changes can only be introduced in major versions, which require a little more care during the upgrade process.
It's definitely safe to do an in-place one-node-at-a-time upgrade for minor versions in the same major series (ie. 4.0-alpha to 4.0.1). Nevertheless it doesn't hurt to take a global snapshot "just-in-case", so you can rollback in case you run into an unexpected issue, but this is just extra safety and not strictly required. Unfortunately there's no official upgrade guide yet, this is something the community is working on to provide soon, but you can find some unofficial ones with a quick google search. Major upgrades are also designed to be harmless, but a little bit more preparation is required to ensure a smooth ride due to potentially non-compatible changes. I've written an upgrade guide sometime ago which can be useful to prepare for a major upgrade, but can also apply to minor upgrades as well to ensure extra safety during the process: http://monkeys.chaordic.com.br/operation/2014/04/11/zero-downtime-cassandra-upgrade.html Cheers and good luck! Paulo Em sáb., 9 de out. de 2021 às 06:56, Attila Wind <attilaw@swf.technology> escreveu: > Hi all, > > I have 2 quick questions > > 1. We have a cluster running 4.0-alpha4. Now 4.0.1 is out and obviously it > would make lots of sense to switch to this version. Does anyone know if we > can do it simply "in place"? I mean we just ugrade the software and > restart? Or it would not work / would be dangerous due to some storage > layer incompatibilities or other risk factors? So better to run a (usual) > data migration process..? > > 2. Actually the above brought the more generic question: is the community > maintaining any kind of guide/readme/whatever one can use to find answer > for similar questions? As a user I see the changelog and that's cool but > that is not providing obvious answers (of course). So I mean some sort of > migration hints/guide. > > thanks! > -- > Attila Wind > > http://www.linkedin.com/in/attilaw > Mobile: +49 176 43556932 > > >
