Re: Fastest way to inject a lot of mail?

On 3/8/24 18:25, John Levine wrote:

So here's a question: I have on the order of 10,000 messages, each with a dozen or so recipients.

That's quite a few discrete messages.

It currently takes about 6 hours on a moderately fast VPS.

Rough math, that's a little over 2 seconds per message.
On one hand that seems a little slow, but on the other hand, maybe not.
How big are the messages?  There's a big difference if it's a few kB of text vs multiple MB of attachments.
Depending on the VPS and the disk(s) backing it, I could see how this may be a disk I/O performance issue.  This seems especially germane on a VPS which is likely shared and may have disk I/O throttling.
I'd suggest looking at this from an OS performance perspective.
If it's Linux, `iostat -x 1` or `sar` or `nmon` are good candidates.
I don't remember, are there any milters in Sendmail?
What are you using for the DNS server?  Is it local to the system or are you dependent on something across the network.  If it's across the network, how far across the network is it?
Are there any errors in any logs?
I would naively think that Sendmail itself could handle messages quite a bit faster.  But I'm probably thinking about SMTP interface vs command line forking.
--
Grant. . . .