SuperSafe=PostMilter (was Re: [Mimedefang] comparemimedefangto mailscanner)

[Jeff Rife]

On 17 Jan 2007 at 23:40, Kevin A. McGrail wrote:

> Sorry to beat a dead-horse potentially but is this a no-brainer setting that 
> everyone running MD should have on their sendmail install?
> 
> I guess the question really is that I have no idea what the benefits or 
> detriments of deferring synchronization of the queue file would be.

The benefit would be speed, especially on a busy server where 
MIMEDefang rejects a large percentage of the messages.  By not asking 
the OS to commit the file to disk (as opposed to letting it hang around 
in OS cache memory) during the first part of queueing, it will 
generally only occur if the OS has time for it (in which case, it's not 
really harming performance).

The detriment would be that if your server crashes (power loss, etc.) 
during the time MIMEDefang is processing an incoming e-mail, then the 
file might not be on physical disk.  This means that the other end 
would just retry when your server is back up, since sendmail would 
never have given the other end a final accept/reject response.  So, you 
shouldn't ever lose data because of this setting (although it could 
definitely be delayed), since the other end *should* retry, but it 
might be the last attempt, or the other end might not be compliant, 
etc.


--
Jeff Rife | "Wheel of morality, 
          |  Turn, turn, turn. 
          |  Tell us the lesson 
          |  That we should learn" 
          |         -- Yakko, "Animaniacs"