So here's the situation.
I've got about 20,000 maildir email accounts chewing up a several hundred GB of space on our email server. Maildir by nature keeps thousands of tiny a** little files, instead of one .mbox file or the like...
So i need to migrate all of these several millions of files from one server to the other, for both space and life-cycle reasons.
the conventional methods i would use all work just fine. rsync is the option that comes immediately to mind, however i wanted to see if there are any other "better" options out there.
Rsync not handling multi-threaded transfers in this situation sucks because it never actually gets up to speed and saturates my network connection, because of this the transfer from one server to another will take hours beyond hours, when it shouldn't really take more then one or two.
I know this is highly opinionated and subjective and will therefore be marked community wiki.