It's always a good idea to have a read of the NEWS.txt file https://github.com/apache/cassandra/blob/cassandra-1.1/NEWS.txt
Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 12/07/2012, at 5:51 PM, Tyler Hobbs wrote: > On Wed, Jul 11, 2012 at 8:38 PM, Roshan <codeva...@gmail.com> wrote: > > > Currently we are using Cassandra 1.0.6 in our production system but suffer > with the CASSANDRA-3616 (it is already fixed in 1.0.7 version). > > We thought to upgrade the Cassandra to 1.1.X versions, to get it's new > features, but having some concerns about the upgrade and expert advices are > mostly welcome. > > 1. Can Cassandra 1.1.X identify 1.0.X configurations like SSTables, commit > logs, etc without ant issue? And vise versa. Because if something happens to > 1.1.X after deployed to production, we want to downgrade to 1.0.6 version > (because that's the versions we tested with our applications). > > 1.1 can handle 1.0 data/schemas/etc without a problem, but the reverse is not > necessarily true. I don't know what in particular might break if you > downgrade from 1.1 to 1.0, but in general, Cassandra does not handle > downgrading gracefully; typically the SSTable formats have changed during > major releases. If you snapshot prior to upgrading, you can always roll back > to that, but you will have lost anything written since the upgrade. > > > 2. How do we need to do upgrade process? Currently we have 3 node 1.0.6 > cluster in production. Can we upgrade node by node? If we upgrade node by > node, will the other 1.0.6 nodes identify 1.1.X nodes without any issue? > > Yes, you can do a rolling upgrade to 1.1, one node at a time. It's usually > fine to leave the cluster in a mixed state for a short while as long as you > don't do things like repairs, decommissions, or bootstraps, but I wouldn't > stay in a mixed state any longer than you have to. > > It's best to test major upgrades with a second, non-production cluster if > that's an option. > > -- > Tyler Hobbs > DataStax >
