I'm sure I must be missing obvious here but why are they not just pushing those mails out directly?
All that gearman buys them here is... a longer delay until the mail is actually sent.
All that gearman buys them here is... a longer delay until the mail is actually sent.
Also, I _hate_ the idea of running an MTA on 30 machines that shouldn't be sending mail.
I don't share your concerns about the MTA (they are lightweight and it's usually helpful to know that sending mails won't block) but to each their own.