On Thu, May 20, 2021 at 11:17 AM Jai Bheemsen Rao Dhanwada < jaibheem...@gmail.com> wrote:
> Thanks for the response, > > Is there a limit on how long I can run in mixed mode? Let's say if > datacenter 1 is upgraded and upgradesstables was run on day 1 and > datacenter 3 is upgraded and upgradesstables runs on day 10. Is that going > to be a big concern? > There is no "limit". The major caveat is a lack of ability to run repair, which may or may not be a problem in your scenario. > > 2 might be strictly safer if you trust internode mixed mode AND have a > way to fail out of a dc and rebuild it without violating consistency. > I tested the mixed mode and it works, but are there any catches that won't > work? > > I am okay to disable repair during this time. > I'd still advise limiting time in mixed mode. You probably don't want to be stuck doing operations in mixed mode, or without repair for too long. An alternative would be to just upgrade one node in each DC first, and monitor that node for any issues. If that node seems stable enough you can roll out to the whole DC, whereas if it encounters problems you can downgrade/fix it without having to go through a complex DC failover. You could even do this in parallel across all your DC's, and thus limit the time you're in mixed mode substantially. -- raft.so - Cassandra consulting, support, and managed services
