I have 3000+ users on my website and just sent them a system message..
The serverload went from 0.50 to 25.+
Users that where comming in that just got a email notification could almost not be served.. at least with huge delays..
The udde mass pm page that i used to sent the command did not return any status, like sent successfully.. instead i waited 15 minutes (meanwhile i checked the server by ssh console ans noticed it was actually executing the command, else, i wouldnt have a clue if it actually registered my 'send' command.), finaly after 15 minutes it said 'server could not be found'..
It would be nice to be able to do blocks at a time, or even schedule a mass pm over a 24 hour period. So blocks of 500-1000 pms are sent at a time..
This will spread the load out over a longer period of time, making the website browsable for those that react on the PM.
Note, i run dedicated, with just 3000 users on the site.. its a 2.4ghz 1g mem machine..
I know that Vbulletin does it by javascript in its mass email system..
VB generates auto reloading pages that do N number of emails at a time and you see each user that gets the message on one seperate line.. the page scrolls down and then either a NEXT button is displayed for the next N number of emails, or the page goes to the next page automaticly.. (admin can set this in the options)