I have a single node cassandra database running since 2 years now... never had any issues with it, but I would like to upgrade it to the latest cassandra (2.1.2 at the time I write those lines), of course without having to shutdown the service.
I have multiple servers at my disposal, that can be brought up to add nodes into a cluster if needed, what would be the procedure to update from my 1.1.0 version to the latest version without having any downtime ?
I know that it will be hard work, since I can't upgrading from 1.1.0 to 2.1.2 straight, I'll have to go through steps because of un-interoperable versions...