Immutable append only persistent log doesn't imply store everything _forever_. If you want to remove something you could add a tombstone record (like Cassandra

Immutable append only persistent log doesn't imply store everything _forever_. If you want to remove something you could add a tombstone record (like Cassandra) and eventually remove the original entry during routine maintenance operations like repacking into a more efficient format, archival into cold storage, TTL handling etc.