I have about 900 GB of uncompressed SQL dumps which have a very large amount of common data. I've been using 7z with the -mx=9
option because I care much more about the size of the archive than how long it takes to compress. That makes an archive around 42 GB.
I just discovered the options mfb
, md
, and ms
. The man page doesn't tell me much about what those options do. What are fast bytes, dictionary size, and solid archive, and when would I want certain settings, especially in my case? The 7-Zip documentation says that level 9 compression has a dictionary of 64 MB. Since my archive is 42 GB, does it help to use a much larger dictionary? Under what circumstances is it useful to use non-default settings?