On Thu, 15 May 1997, Philip Hazel wrote:
> On Wed, 14 May 1997, Christoph Lameter wrote:
>
> > We installed exim 1.62 on a Linux system (Debian 1.3) and tried to use it
> > to sent out e-mail regarding a TV series "Mad about you". We needed to
> > sent out 100.000 mails and since I have had around 80.000 on some mail
> > exploder I thought it would not be such an issue.
>
> I do hope this wasn't unsolicited mail. The plague is getting worse. We
> have added 30 addresses to our block list this week alone.
It wasn't. These where people who had signed up for a newsletter.
>
> > This in itself brought a load of 3 on the system. The message queue grew
> > to 25.000 entries (in part because of some permission issues with the mail
> > directory of the user who got the errormessages back).
>
> I believe Linux is one of the systems that suffer performance problems
> when there are very large numbers of files in the same directory. I am
> planning to upgrade Exim so that it can be configured to split the mail
> spool directory into 62 subdirectories. This is not actually going to be
> very much work; I just have to find the time to do it.
That would probably help a lot.
>
> > Delivery for off site messages was also very slow. We could never get exim
> > to deliver more than one message per second.
>
> 3,600 per hour. Hmm. John Henders reported yesterday on a system that
> was doing about double that, but he was using a dual processor sparc 20
> with 512 meg of ram. Of course, the speed of the network link is also
> relevant.
The max was about 2-4 per second which is inline with what John reports.
I would have expected something more like 200 messages per second.
> > Finally it was decided that
> > exim is unsuitable for such a purpose. Qmail is lurking on the horizon...
>
> I do not believe that any one mailer can suit everybody. There are
> several to choose from. I have no problem with people deciding that some
> other product suits their purpose better than Exim. Heck, I'm not trying
> to sell it to make money... :-)
:) I know. Christoph recommended exim and so it was tried...
> > Is there any way to get exim to do faster deliveries?
>
> Bigger box? Faster network connection?
Have big box and fast network.
> > The queue management of exim is a catastrophe for larger projects. Its is
> > slow and unreliable and unmanagable.
>
> I must suffer from an imagination deficiency, because I never considered
> situations where there were 25,000 messages on a spool. Here we rarely
> have more than a few hundred at the worst of times, so I was thinking a
> few thousand would be the extreme. I think the slowness may in part be
> due to the file system problem mentioned above.
That certainly makes sense to me.
> > Also had segfaults due to a corrupt Berkeley DB database. After
> > removing the database things went almost back to normal again.
>
> The corruption of DB databases has never been satisfactorily explained.
> (The segfaults happen inside the DB functions.) Another thing I hope to
> get to fairly soon is to investigate the new release of Berkeley DB, as
> well as gdbm, and also a general look at the database area. But as
> always, there is too much to do and not enough time.
>
> Philip
>
> --
> Philip Hazel University Computing Service,
> ph10@??? New Museums Site, Cambridge CB2 3QG,
> P.Hazel@??? England. Phone: +44 1223 334714
>
>
