Messages to a Distribution List propagation time

[pviolant]

How long does it take for a message to the all Suscriber Distribution List propagate to all users on a 4000 - 5000 user system?

[lindborg]

hard to say - depends on yoru Exchange environement - we hand the message off to Exchange to deliver when it goes to a DL (i.e. we don't "flatten" the list ourselves and send it to each user or anything) - given Exchange's "single source messaging" scheme for group messages it really depends on the number of servers the users are spread over, their connectivity, other Exchange traffic - I don't think there's any reliable way to predict this without just testing it on your system.

[pviolant]

1 Unity server - message store off box

2 Exchange servers ~ 2500 users each. The Broadcast message would be @ midnight so very little user traffic. All servers are on the same subnet, same wire (100BT on the same catalyst switch line module).

[lindborg]

That should be pretty quick... Each Exchange server that homes 1 or more recipients of the message will only get one copy of the actual message - everyone on that box will then get a pointer to that message in their inbox.

But still - I can't give you a time frame to work with here - you'll just need to run some tests. Just keep in mind it's not actually sending out 4,000 copies of the message so I'm imagining this will go much quicker than you may think.