We were performing an upgrade of our cluster from 1.1.10 version to 1.2.4 . We tested the upgrade process in a QA environment and found no issues. However in the production node, we faced loads of errors and had to abort the upgrade process.
I was wondering how we ran into such a situation. The main difference between the QA environment and the production environments is the Replication Factor. In QA , RF=1 and in production RF=3.
The other observation is that the node which was being upgraded is a seed node in the 1.1.10. We aborted right after the first node gave the above issues. Does this mean that there will be an application downtime required if we go for rolling upgrade on a live cluster from 1.1.10 version to 1.2.4 version ?