Hi, Need input on cassandra upgrade strategy for below: 1. We have Datacenter across 4 geography (multiple isolated deployments in each DC). 2. Number of Cassandra nodes in each deployment is between 6 to 24 3. Data volume on each nodes between 150 to 400 GB 4. All production environment has DR set up 5. During upgrade we do not want downtime
We are planning to go for stack upgrade but upgradesstables is taking approx. 5 hours per node (if data volume is approx 200 GB). Options- No downtime - As per recommendation (DataStax documentation) if we plan to upgrade one node at time I.e. in sequence upgrade cycle for one environment will take weeks, so DevOps concern. Read Only (No downtime) - Route read only load to DR system. We have resilience built up to take care of mutation scenarios. But incase it takes more than say 3-4 hours, there will be long catch up exercise. Maintenance cost seems too high due to unknowns Downtime- Can upgrade all nodes in parallel as no live customers. This has direct Customer impact, so need to convince on maintenance cost vs customer impact. Please suggest how other Organisation are solving this scenario (whom have 100+ nodes) Regards Shishir
