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Re: Newbie: Slow scheduling?
On Wed, 30 Jun 1999, Matti Aarnio wrote:
>
> Lets see what happens under ZMailer:
>
[..]
>
> So, for each delivery, ZMailer does at least 13 directory MODIFYING
> operations, moving from one directory to other is here assumed equally
> costly to simple rename within one directory, or file creation and unlink.
[..]
> Now I do tend to think that those directory transactions are the most
> expensive part of the email delivery in the usual UNIX environment.
>
> In this sense 'sendmail' does pretty lightweight set of dirops; mere
> 6, I think (creating and deleting 3 files in 'mqueue' directory.)
>
[..]
>
> That said, 5000 messages in 3*60 seconds means about 28 deliveries per
> second, or about 360 dirops per second! You must have very recent
> Linux at that PPro of yours, which has asynchronous metadata..
> (Doing same in 2*60 seconds would mean about 540 dirops per second;
> mere 2 milliseconds per dirop ... ok, just and just possible with
> synchronously written metadata, if the system doesn't need to actually
> write/read file data content (all in cache), and your disks are brand
> new speed demons, or you operate on RAMDISK..)
Isn't it a great idea? Having the $POSTOFFICE in a ramdisk?
Mmm.. let me see:
(system almost idle, empty mailq)
$ time ./mailflooder.pl
real 4m43.440s
user 0m38.830s
sys 0m37.200s
$
This real time has varied from 5 to almost 8 minutes, and I calcule(!)
one or two minutes more to deliver the rest of the mailq. Time flies
faster than I thought... anyway it's very fast.
Killing syslogd also increases speed.
> The term you are looking for is: latency
Yes, that's the word.
Btw, another thing I like much is the policytest(). I've been trying to
use Procmail to reject spam, but most of what I could do is to send it to
/dev/null. I receive mail at 14.400baud, and it would be nicer the
ZMailer's blocking method.
For what I've seen, I can rejet by HELO/EHLO, FROM, and TO fields. Can I
reject from other fields? I.e: if Organization matches 'spam empire' or
X-Mailer matches 'Outlook' then reject it.
Thanks in advance,
---
Dani Pardo, dani@enpl.es
Enplater S.A