I run a Debian Linux mailserver for a few little companies that stores its emails in a Maildir structure and therefore each mail as a seperate plain text file.
Altogether these files are as large as about 45 GB.
Even though I am backing up the files online I want to download them to store them on another physical backup media.
Evaluated statistically each 5th mail has one file attachment being as large as about 1.2MB. What would be a good compression for this files? The speed of the compression is of low priority because I do only work on archived data not the productive one.
I am not asking for the "best" solution as I know there isn't one but am looking for your recommendations.