[unisog] When you really need to blast email

Reg Quinton reggers at ist.uwaterloo.ca
Thu Mar 13 17:46:39 GMT 2008

Michael Holstein [michael.holstein at csuohio.edu] asks
> Our safety folks are working a campus-wide "emergency notice" system,
> where one option will be email (the logic behind that is outside the
> scope of this technical question).

We do mass mailings to ~20+K for student e-voting (invitations to vote which
are not personalized -- same message to everyone) where students are
scattered about on different servers probably very much like yours. The
practice has been to take the list (alpha sorted, not sorted by hostname),
chunk that into shorter lists of 100 and blast those out. I.e. 200 messages
each with 100 recips rather an 1 message with 20,000 recips.

To date we've not had the problem you describe. And yes we have lots of
folks on hotmail, etc. The sending (modest Unix server) usually takes about
10mins with most delivered PDQ. The mail queue cleared within 30mins. No you
don't get to everyone, but you get to hit a lot PDQ and that's probably
enough for the "emergency notice".

If you take a single message to ~20+K users you're going to end up with very
long lists to popular mail servers who will, rightly, detect your mail as
spam and may well black list your site. Chunking helps for us ... so far.

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