The host aretha was intended for storage as it is equipped with a large but slow HDD. It is being inappropriately used for resource-intensive tasks such as making MB JSON dumps, running MB Server test instance, running Postgres test instance. It has been causing load issues for years, see MBS-12538’s attempt to address those.

Only barman/ftp/other backup things should run on aretha.
A new host should be set up to run the rest.