Thank you On Wednesday, May 19, 2021, Jeff Jirsa <jji...@gmail.com> wrote:
> > Schema changes are not guaranteed to work across versions (especially > major versions where the internode protocol changes) - imagine the new > version adds a new primitive type or collection, adding a new collection on > the new version won’t be interpretable by the old version as anything > meaningful, so old won’t get schema changes from new. > > Adding and removing DCs both require repair to do safely (without > violating consistency, at least). > > Adding new nodes to an existing dc MIGHT work depending on which version > you add and which version the losing replicas are running. > > > > On May 19, 2021, at 10:13 PM, Jai Bheemsen Rao Dhanwada < > jaibheem...@gmail.com> wrote: > > > Thanks for the suggestions. > > Few more questions on the mixed mode. Can I perform the below operations > on my cluster in the mixed mode? > > 1. Add a new datacenter with the new version > 2. Remove a datacenter > 3. Add more nodes to the upgraded or non-upgraded datacenter > 4. Schema changes > > I haven't tested these yet, but just trying to gather information about > do's and don'ts > > > On Wed, May 19, 2021 at 7:39 PM Jeff Jirsa <jji...@gmail.com> wrote: > >> Incredibly slow and has no real benefits beyond a single canary. >> >> >> On May 19, 2021, at 7:19 PM, rammohan ganapavarapu < >> rammohanga...@gmail.com> wrote: >> >> >> How about option 1? Any issues with option 1? >> >> On Wed, May 19, 2021, 6:58 PM Kane Wilson <k...@raft.so> wrote: >> >>> 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 >>> >>
