On Tue, Apr 13, 1999 at 11:27:15AM -0400, Dave Sill wrote:
> Silver CHEN <[EMAIL PROTECTED]> wrote:
> >
> > Someone said that qmail is weaker if I send many 'RCPT TO:' in one SMTP
> > transactions than sendmail. Well, I don't know the inside story, but I
> > do worry about that statement.
>
> Don't worry. There are very rare situations in which sendmail can be
> faster than qmail, but in 99+% of actual usage, qmail is *much*
> faster than sendmail.
>
> > Usually the newsletter (or big mailing list) admin. will use 'bulk' mail
> > to distribute their message, i.e. one message with 'many' recipients.
> > And they will sort the recipient lists before sending to MTA too.
>
> It's probably better *not* to sort the lists with qmail because it
> will pound on the receiving systems. If you randomize the recipients,
> qmail's impact on receiving systems will be spread out.
>
> > I think this flow is ok, but I don't know if this kind of behavior (one
> > message w/ many recipients, and sorted lists) is suitable for qmail?
>
> One message with many recipients is good. Sorted lists--at least,
> sorted by domain or MX--is not *bad*, but may subject pooorly run
> sites to more load than they can handle.
>
> > Will qmail spwans a lot of processes for 'one' such SMTP transaction?
>
> Yes, it'll spawn up to `concurrencyremote' processes, assuming
> negligable local recipients. This is the big reason that qmail is
> faster than sendmail: with sendmail, one process delivers to all
> recipients, and only one connection is ever open to a remote
> site. qmail, on the other hand, uses up to conncurrencyremote
> (default: 20) processes, up to conncurrencyremote of which may be
> connected to any given remote site at one time.
Hmm very untrue in fact. Sendmail will under several circumstances [none of which I
will explain here but some of which are quite common] open several connections to the
same remote host, even for the same domain. The real problem is that sendmail is not
intelligent in this _at_ _all_. It'll just fire up another queue runner when it feels
like [when someone does sendmail -q (any user will do), or when mail comes in
(although the runner will then only attempt delivery of the mail that just came in),
or when given an ETRN (I give my fallback MX 7 ETRN commands when I dialin, of which
2 are for the same domain, which means sendmail always opens up 2 connections to my
qmail-smtpd :)]
hmmm some long sentence in there :)
Greetz, Peter
--
| 'He broke my heart, | Peter van Dijk |
I broke his neck' | [EMAIL PROTECTED] |
nognixz - As the sun | Hardbeat@ircnet - #cistron/#linux.nl |
| Hardbeat@undernet - #groningen/#kinkfm/#vdh |
