The sqlite backed is deprecated, and the redis backend is the default
since rspamd 2.0.
Not having redis started results in such errors:
rspamd_redis_init: cannot init redis backend for BAYES_SPAM
To migrate the sqlite database, run
rspamadm statconvert --spam-db /var/lib/rspamd/bayes.spam.sqlite --ham-db /var/lib/rspamd/bayes.ham.sqlite -h 127.0.0.1:6379 --symbol-ham BAYES_HAM --symbol-spam BAYES_SPAM
The current module implements the recommended configuration that this
utility prints out.