Mailinglist Archive: opensuse (3996 mails)

["Carlos E. R." <robin1.listas@xxxxxxxxxx>]

The Friday 2004-09-10 at 13:10 -0500, Danny Sauer wrote:

> > Communigate is fast and rock-solid if a bit no-frills, and supports the 
> > features you've mentioned.    While SpamAssassin is open source and very 
> > sophisticated, it has one problem that has caused us a lot of difficulty: all 
> > spam processing is done entirely in RAM, with no ability to swap to disk if 
> > the server gets slammed.  
> 
> SA doesn't do anything to lock itself in physical RAM.  If the server's
> under high load and SA is scanning lots of messages, then the kernel can't
> very well swap it out, since SA will be receiving most of the available
> time slices.  I'm not sure how the processing would work outside of RAM,
> anyway.  What's it gonna do - write a file and then read the file off
> of the disk several times? :)

The trick is to throttle the mail being sent to SA; you can limit the 
number of local mail delivery processes postfix opens (assuming that SA is 
called from there), so that you don't have more than a certain number of 
SA processes running. I assume qmail has a similar adjustment.

If you don't limit that number, you may end having hundred of SA processes
(one per mail), using all ram available and swapping to disk when ram is
spent.  This does effectively grind any mail to the ground on its knees.

If you limit the number of processes, mail will simply be spooled and 
wait. It is fact much faster.

-- 
Cheers,
       Carlos Robinson