From owner-freebsd-isp Sat Mar 14 09:01:22 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id JAA02757 for freebsd-isp-outgoing; Sat, 14 Mar 1998 09:01:22 -0800 (PST) (envelope-from owner-freebsd-isp@FreeBSD.ORG) Received: from mail.ruhrgebiet.individual.net (in-ruhr.ruhr.de [141.39.224.38]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id JAA02746 for ; Sat, 14 Mar 1998 09:01:20 -0800 (PST) (envelope-from bs@devnull.ruhr.de) Received: (from admin@localhost) by mail.ruhrgebiet.individual.net (8.8.5-r-beta/8.8.5) with UUCP id RAA01651; Sat, 14 Mar 1998 17:52:54 +0100 (MET) Received: from rm.devnull.ruhr.de [192.168.22.75] by devnull.ruhr.de with smtp (Exim 1.73 #1) id 0yDtoN-0000Mh-00; Sat, 14 Mar 1998 17:29:27 +0100 Received: from bs by rm.devnull.ruhr.de with local (Exim 1.73 #1) id 0yDtyF-0000JS-00; Sat, 14 Mar 1998 17:39:39 +0100 To: "Andras Tudos - Computronic, C3" Cc: freebsd-isp@FreeBSD.ORG Subject: Re: Scalable mail server References: <3.0.2.32.19980312213104.01060870@computronic.hu> Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit From: Benedikt Stockebrand Date: 14 Mar 1998 17:39:39 +0100 In-Reply-To: "Andras Tudos - Computronic, C3"'s message of "Thu, 12 Mar 1998 21:31:04 +0100" Message-ID: <87lnud8bw4.fsf@devnull.ruhr.de> Lines: 56 X-Mailer: Gnus v5.5/XEmacs 20.3 - "Vatican City" Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org "Andras Tudos - Computronic, C3" writes: > we have to scale our qmail based mail server (with a custom made www > frontend) to multiple machines to be able to serve ~100000 users and more. > Currently we have a single server based heavily overloaded system with > 30000+ users. We have many plans, but I would prefer to hear how others > would start to construct such a system. We build all the machines ourselfs > (including PII based PCs, RAID, network) and write the necessary code. What's your resource bottleneck? Until you've found out about this you're only fighting with a blindfold on. > All ideas, especially real world experiences are warmly welcome... > (Especially file-system, >From experience with news and UUCP: Do you happen to have a single /var(/spool)?/mail directory holding all users mail boxes? If so, split that up first. And if you've got a flat /home/* hierarchy, do the same there, too. Files are searched via linear search on directories, and that becomes *excessively* expensive with large directories. Especially with UUCP-forwarding news servers this can be absolutely devastating. > user database and redundancy issues are critical. RAID arrays are always reasonable for reliability issues. > Would you use SMP with dual PIIs or 2.2.5? Some SMP developers are probably going to kill me for this, but I'd stay away from SMP if I can help it. The kernel SMP support may be fine. Maybe the libraries are fine, too. But don't rely on every single userspace program you use to work reliably on SMP systems. And debugging problems that only occur twice a week isn't much fun, especially on production systems. Besides, I wouldn't really expect CPU load to be the limiting resource anyway. > NFS issues? As a personal opinion: Don't. It's a resource hog. And if a machine goes down this will cause heaps of problems on the remaining machines. > Postgres instead of passwd? Do some performance analysis before you get into this sort of stuff. Unless I'm mistaken the /etc/s?pwd.db should be reasonably fast except when running pwd_mkdb to modify it. Ben -- Ben(edikt)? Stockebrand --- Un*x system administrator looking for a job To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message