I just upgraded to 2.4 this morning and the whole cache administration section is there. Awesome! I don't really understand caching: not awesome!
I see that it seems to come down to 6 "basic" options: file cache, memcache, memcached, mongoDB, session cache, static request cache
if you have nothing else you'll have these three: file cache, session cache, static request cache
Those three are pretty straight forward and seem to be either a memory or disk cache (haven't read into it). What I'd like to know more about is which of the other 3rd party implements are "best" and how to "best" implement them.
our environment is split between two servers:
moodleweb: apache, php, apc, 2nd data volume (for moodledata), 6Gb ram