Just in case anyone cares..
On Tue, Nov 16, 2004 at 05:10:17PM -0500, Greg A. Woods wrote:
> [ On Tuesday, November 16, 2004 at 21:36:32 (+0100), Marcin Owsiany wrote: ]
> > Subject: Re: [exim] exim capabilities fo 10-30 K email accounts
> >
> > On Tue, Nov 16, 2004 at 02:05:51PM -0500, Greg A. Woods wrote:
> > > Depending on how many limits you put on your users it's possible to
> > > handle upwards of 15,000 users on a measly little PII/300Mhz with 512MB
> > > of RAM and a decently fast disk subsystem. The particular system I have
> > > in mind also serves all the personal web pages for those users (maybe
> > > 25% of users have homepages, some quite busy but most never get hit).
> >
> > Could you please tell how many block reads/writes per second you get at
> > peak load time? (sar/iostat/whatever)
> >
> > Because statements like yours make me wonder whether it is my hardware
> > that underperforms, or it is my users that are so special. :-)
>
> Undoutably it's your users! :-)
[...]
> Inetd's much more primitive rate limiting controls cause us far more
> headaches with the constant POPping idiots, especially when a family
> computer might have 8 or more mailboxes that it checks simultaneously
> every five minutes all day long.
In our case this turned out to be those so called "popping idiots"
combined with an old courier-pop3d which needs to read whole mailbox
_contents_ at each login (I've heard that newer releases cache the
needed info). After:
- patching maildrop to store the needed information as a maildir tag,
- and patching pop3d to use that information when available,
- and updating all maidirs
reads/sec became more like yours (i.e. sane, and not over an order of
magnitude higher), loadavg is around 1.5 most of the time.
Marcin
--
Marcin Owsiany
porridge@???
