If you run a CPAN mirror, please subscribe to the announcements-only cpan-mirrors mailing list by emailing cpan-mirrors-subscribe at perl.org.
From a posting just made there (first in ~7 years):
If you are currently mirroring from rsync.nic.funet.fi or (in particular) from ftp.funet.fi, please change your mirror source to be rsync://cpan-rsync.perl.org/CPAN/ -- let us know at firstname.lastname@example.org when you've changed the mirror source so we can update the MIRRORED.BY file.
Other related news: cpan-rsync.perl.org will soon be a "distributed tier 1 mirror" — and we need tier 1 rsync mirrors! Rather than use plain rsync, we'll use our new "instant mirroring" system that allows a mirror to be up-to-date within 30 seconds of a file being uploaded to PAUSE with very little overhead.
If you want to help be a tier 1 mirror, please see the wiki page on the "instant mirroring" test: https://github.com/perlorg/cpanorg/wiki/Instant-update-mirroring — send a mail to email@example.com to get an rsync username/password for the "tier 0 master mirror" if you are going to setup a tier 1 rsync mirror.
And just to be clear: If you are mirroring from anywhere else than FUnet, you can just keep your current mirroring arrangement in place.