Request For Comments: Proposed method for fallback lists
I'd like the input of the Debian developers on my ideas for providing
redundant mailing list service through the use of mirror and the use
of DNS MX records. If you would like to send comments to me or to the
list, please do so.
At present, my duties as mailing list administrator seem to mostly
include holding the hands of people who can't seem to get
subscribed/unsubscribed, and to maintain some semblance of a backup of
the list files to be able to recover from a crash on lists.debian.org,
wherever that may be.
I'd like to extend the disaster recovery plan to use my desktop
workstation as the secondary listserver, to be used if sending sites
determine that debian.novare.net (currently posing as
lists.debian.org) should appear to be unreachable. My proposed plan
would utilize the backup which I maintain using mirror and DNS MX
records.
Once an hour, I mirror the entire /var/list tree from the listserver
to /local/debian-lists on my workstation. I've created local lists on
my workstation in /var/list, with symlinks to /local/debian-lists as
appropriate. I've changed the appropriate Smartlist files to make the
lists appear to come from *@lists.debian.org (although the headers
will certainly show the difference).
One of the biggest issues that I can forsee is the need to handle
subscriptions and unsubscriptions properly. My suggested approach is
to have the individual list -request addresses aliases to both the
master site (debian.novare.net) and handled locally. If those
requests are not passed to the master server and are made locally
only, the mirror process will replace the changes with unchanged files
from the master site.
Another issue which I would like some input on is digests: Each of the
digest/undigested list pairs works together (debian-user has a
recipient as debian-user-digest). If the secondary site handles
distribution for the undigested list, it will get the email intended
for the digested list. If the master site is unreachable for a short
period, the secondary site will begin building a separate digest.
Should the digest lists be explicitly handled on the master server
only? Should the secondary site merely send its own digested
messages? Should the secondary site send digests AND pass messages to
the master for inclusion in the master's digest also?
The third issue which I see as worthy of discussion is: Immediate
handling or merely standby capability. By immediate handling I mean
that my workstation, acting as a second MX for lists.debian.org, could
immediately distribute mail for lists.debian.org that it received
(meaning that it "accepts" mail addressed to lists.debian.org). By
standby capability I mean that the machine remains a second MX for
lists.debian.org and queues mail destined for debian.novare.net, but
only distributes mail for the lists if debian.novare.net is deemed out
of commission. Perhaps it is an easy decision for immediate handling,
but I'd like to hear what you folks have to say.
Being the techno-character that I am, I'm sure that I've unclear on at
least something. If this matter interests you and you'd like further
explanation or clarification, please let me know. I welcome your
thoughts on this idea.
Thanks,
Pete
--
Pete Templin, Debian List Administrator listmaster@lists.debian.org
Reply to: