Cannot get Redis persistence working on premise

Just wondering if anyone managed to get redis persisting when the docker containers are restarted.

I’ve added the a custom redis.conf file like so:

save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
# The filename where to dump the DB
dbfilename dump.rdb
# The working directory.
dir /data

This file is copied to the redis container when starting and the command redis-server /usr/local/etc/redis/redis.conf

I have a cron job that copies the dump.rdb file to an external storage location regularly. This file is copied back to /data when the containers are restarted but it doesn’t seem to be loaded.

Can anyone see where I am going wrong?