I rather wish that NMH would take a "Path" to be... well.. $PATH-like
thing, such that I could move folders to an archive machine, with NMH
being aware that they are elsewhere. Ideally, it could be told that
they are even RO, burnt on DVD or something like that.
Not quite what you want, but in case it's useful:
I started using mairix as my MH search tool recently, and it supports a
vague approximation to this: I can throw an entire folder into a
.mmdf.xz file on my archive drive and tell mairix to index that file, so
whenever I use mairix to search for something with a long-enough time
window it'll extract these old emails from the .mmdf.xz into my +s
search results folder. Can be a bit slow if it finds something at the
end of a very big archive, but that doesn't happen too often.
The result is that I currently have around 300 old archived folders
indexed in addition to all my current mail. It enables a much more
streamlined .Mail folder while still giving full access to all the old
stuff. For me it's been pretty transformative.
Conrad