I’m not a fan of appendonly and prefer snapshotting at an interval where I can tolerate potential, small loss. I like the following as a starting point:
redis-server --save 300 1 --save 60 100 --appendonly no
You also haven’t mentioned where the data is stored. Is this in a Docker volume or running natively in an OS (I’m assuming the latter, given ARM9 and Ubuntu)?
With either approach, you should be able to see your persistence file being written while Redis is running.