We have a requirement to re-install all software monthly, to address security patches, etc. So once a month I take a backup, blow away the EC2 box, then re-install and restore the backup.
This month, as part of upgrading to 1.18.2, something went wrong.
I’m installing Cassandra 4.1.0. It won’t start up. If I install 3.11.14, it starts up, but FrontLine doesn’t see any of the data.
I need someone with a deeper knowledge of how things work under the covers to help me get things running again. Please! 
Hi John,
If you want to upgrade from Cassandra 3 to Cassandra 4, you have to edit the cassandra.yaml conf file and change num_tokens from 16 to 256 to restore Cassandra 3’s value as it’s also stored in the database and causes an incompatible crash on boot.
Also, make sure you’re using the same Linux user as before, so that the process owner can properly read and write the files.
If you still run into an issue, please provide your logs (you might want to reach out privately on the Jira Support Portal).
Cheers
Okay, I’ll keep with 3.x to keep things simple.
Now, any thoughts as to why FrontLine thinks the database is empty, or how to get it to see it again?
First please check that the Cassandra service is running.
Then, please provide your Gatling Enterprise server logs.