Timo Sirainen writes:
Keeping ACLs in SQL is different from keeping the whole mailbox data
in SQL. Currently the ACL plugin supports only vfile backend, but it
wouldn't be too difficult to add support for SQL backend.
Having ACLs in SQL allows companies to have a centralized place for all ACLs.
For instance our mail tables are generated from other tables.
Users update the "primary" tables in a management screen. A program takes data from these primary tables and populates the appropriate tables. All backend mailstore machines connect to the database to get their information.
If ACLs were on files one would have to have a specialized program to grab data from a centralized database to create the local files. For one machine that is likely ok but for many machines it starts to get complex (ie you have to sync all the programs accross all the servers to be up to date).