[MM3-users] Kind of off-topic, but Mailman related

I back up my server using "borg" to send it to a different server. I keep 7 dailies, 4 weeklies and 6 monthlies. When I used Mailman 2, my borg backup size stabilized and never seemed to grow much. But since switching to Mailman 3, my backup size has been growing, seemingly without bounds, even though the amount of disk space I'm using on the Mailman server isn't growing much. I suspect this might be because of the way it's storing stuff in PostgreSQL instead of in the file system is fooling borg's deduplication methodology. Does anybody else have any experience with borg and Mailman 3? Should I exclude postgreSQL from the backup and do a separate pg_dumpall?

-- Paul Tomblin