From owner-freebsd-hackers@FreeBSD.ORG Tue Jul 6 18:53:08 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8F55A16A4CE for ; Tue, 6 Jul 2004 18:53:08 +0000 (GMT) Received: from mail-in-07.arcor-online.net (mail-in-07.arcor-online.net [151.189.21.47]) by mx1.FreeBSD.org (Postfix) with ESMTP id CDC9743D41 for ; Tue, 6 Jul 2004 18:53:07 +0000 (GMT) (envelope-from mailnull@mips.inka.de) Received: from kemoauc.mips.inka.de (dsl-082-083-163-172.arcor-ip.net [82.83.163.172]) by mail-in-07.arcor-online.net (Postfix) with ESMTP id 4D74E102F12 for ; Tue, 6 Jul 2004 20:53:06 +0200 (CEST) Received: from kemoauc.mips.inka.de (localhost [127.0.0.1]) i66Ir5fa014852 for ; Tue, 6 Jul 2004 20:53:05 +0200 (CEST) (envelope-from mailnull@kemoauc.mips.inka.de) Received: (from mailnull@localhost) by kemoauc.mips.inka.de (8.12.11/8.12.11/Submit) id i66Ir5jL014851 for freebsd-hackers@freebsd.org; Tue, 6 Jul 2004 20:53:05 +0200 (CEST) (envelope-from mailnull) From: naddy@mips.inka.de (Christian Weisgerber) Date: Tue, 6 Jul 2004 18:53:04 +0000 (UTC) Message-ID: References: <20040705205100.88989.qmail@web53307.mail.yahoo.com> Originator: naddy@mips.inka.de (Christian Weisgerber) To: freebsd-hackers@freebsd.org Subject: Re: concurrent scp transfers (and a testing methodology ?) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Jul 2004 18:53:08 -0000 Joe Schmoe wrote: > However, I wonder how well this relates to how many > ssh sessions (scp file transfers, specifically) that a > FreeBSD server can handle. Can anyone throw out some > basic numbers for this ? Assuming a 1ghz p3 and 2gigs > of RAM, and assuming that everyone is transferring a > totally different file. In LAN environments, scp is conspicuously CPU limited. A P3/1GHz will be able to push out a file at about 6MB/s. Divide by desired number of files. Just what transfer rates did you have in mind? > I would think the major bottleneck would be disk I don't think so. If you have many concurrent transfers of different files spread out wildly over the disk, you might get the disk to thrash, but it isn't clear that it will still matter at this point. Check some "random reads" benchmarks for your vintage of disk. > (like, does SMP help a lot here, or just a little ?) A lot, as far as SMP goes. Alternatively, a lowly VIA C3 Nehemiah with its on-core AES engine should happily beat your usual high-end P4/Athlon/etc at this task. (I don't know whether FreeBSD integrates the AES engine in userland. OpenBSD does.) -- Christian "naddy" Weisgerber naddy@mips.inka.de