Date: Wed, 20 Jun 2001 12:53:59 -0700 (PDT) From: Matt Dillon <dillon@earth.backplane.com> To: void <float@firedrake.org> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: max kernel memory Message-ID: <200106201953.f5KJrxm14311@earth.backplane.com> References: <Pine.LNX.4.21.0106201112090.1235-100000@vangogh.indranetworks.com> <200106200704.f5K74M706441@earth.backplane.com> <20010620193151.C2973@firedrake.org>
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: :On Wed, Jun 20, 2001 at 12:04:22AM -0700, Matt Dillon wrote: :> :> A web proxy could be :> round-robined fairly easily, but for a mail relay it is often a good :> idea to split the incoming and outgoing mail into two separate round :> robins (two separate groups of machines). : :Why's that? So you can tune each type of machine appropriately for :the task? How would you tune incoming and outgoing mail servers :differently? : :-- : Ben That's the idea. A mail relay would be tuned for its purpose. The queueing characteristics for relaying to internal hosts are going to be very, very different then the queueing characteristics for relaying to extern (internet) hosts. So different that by separating the functionality you can squeeze out considerably more performance out of each machine and, as a bonus, make the overall system more reliable. Now if you get a deluge of mail in one particular direction, it will not effect mail going in the other direction at all. So instead of having 6 generic mail relay boxes in a round robin you might instead have 4 boxes to relay outgoing mail to the internet and 2 to relay incoming mail to internal machines, with the outgoing boxes tuned to handle huge queues and the incoming machines tuned to handle lots of incoming connections but smaller queues (relaying to internal hosts being much faster, less prone to hicups, and the queue-runner's persistent connection caches being much easier to maintain). -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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