I'm retrieving my email using offlineimap to a local maildir which I am indexing with mu (reading/writing is done using mu4e in emacs).
After loading all emails from the server my Maildir folder is about 1.1GB in size. However, the very same account takes much less space when downloaded with thunderbird (less than 500Mb).
I assume that the reduction in disk space is due to some compression so my question is
How can I reduce the disk usage of my Maildir setup without losing email history?
It might be because there are messages that are contained in multiple imap folders and are thus getting duplicated. For example, in Gmail, the "[Gmail]/All Mail" and some other folders are usually redunant. I use
in .offlineimaprc to avoid this problem. depending on what subset of folders contains all messages without much redundancy, you might need to do things differently.