On Wed, Jul 16, 2003 at 11:26:35AM +0100, Randy Orrison wrote: > David Fokkema wrote: > >Many, many mails were downloaded (thanks to this fine group, :-) and > >almost immediately, my server became irresponsive. I managed to squeeze > >in and run top which came on after three minutes and saw my load > >increase from 20 to 30 to 50 to 77.81. I had a few exim processes and > >_lots_ of amavis processes running. My server started killing processes > >(out of memory) and I decided to power down (using the button, nothing > >else worked). > > I had a similar problem not long ago after upgrading spamassassin and > going on holiday. > > >1. What can I do when my server overloads like this? Logging in was > > _very_ difficult or not possible (timeout of 60 seconds on login > > prompt...) > > Not sure about this one, I don't recall what I did in my panic :-( > Probably killed fetchmail and waited it out. > > >2. How do I limit the number of exim processes? Exim is run from inetd > > and the infopages showed me that smtp_accept_max will not work. Is > > this indeed a problem? Should I run exim as a separate daemon and > > enable smtp_accept_max (or keep it at default 20, better than no > > limit...)? Is every server which runs exim from inetd vulnerable to > > this (whether deliberate or not) DoS attack? > > The solution (which I found after googling around for a while) is to add > the following settings in your exim.conf file: > > # When this option is set, no message deliveries are ever done if the > # system load average is greater than its value, except for deliveries > # forced with the -M option. If deliver_queue_load_max is not set and > # the load gets this high during a queue run, the run is abandoned. > # There are some operating systems for which Exim cannot determine the > # load average (see chapter 1); for these this option has no effect. > > deliver_load_max = 4 > > # If the system load average is higher than this value, all incoming > # messages are queued, and no automatic deliveries are started. If this > # happens during local or remote SMTP input, all subsequent messages on > # the same connection are queued. Deliveries will subsequently be > # performed by queue running processes, unless the load is higher than > # deliver_load_max. > # There are some operating systems for which Exim cannot determine the > # load average (see chapter 1); for these this option has no effect. See > # also smtp_accept_queue and smtp_load_reserve. > > queue_only_load = 4
This seems very nice! Have to try out if amavis is run before or after queueing (is this a word?) otherwise this won't have effect. If amavis is run _after_ queueing and before delivery, this is great! Thanks, David -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
