From owner-freebsd-questions@freebsd.org Wed May 6 19:55:56 2020 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 3D5D42DE179 for ; Wed, 6 May 2020 19:55:56 +0000 (UTC) (envelope-from bob@proulx.com) Received: from havoc.proulx.com (havoc.proulx.com [96.88.95.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 49HS5722MGz46pZ for ; Wed, 6 May 2020 19:55:54 +0000 (UTC) (envelope-from bob@proulx.com) Received: from joseki.proulx.com (localhost [127.0.0.1]) by havoc.proulx.com (Postfix) with ESMTP id 59AE7467 for ; Wed, 6 May 2020 13:55:48 -0600 (MDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proulx.com; s=dkim2048; t=1588794948; bh=eIeFwfluL0H4GbLl8cEWTEtexGOUccGhQ6VX7NywrT4=; h=Date:From:To:Subject:References:In-Reply-To:From; b=kxCtuuhkY31FXoDOzSZu/2A7kwgPGI7e1cbQvhwbu9RSiO8fDlfegv8T5lEkdeD80 PGz68H/TG4U7Ep8l7k6iK2yeEGX+eI4fSyRSCeYzqw1R1lOngVbStofsRKrg/YuALT JVvGAjQh7iiHZ4xoxrh8a1QEMS1vr+fpUCqwgSqRvTzSiZe2r1wKCFYATVkhWl9e94 4cIuLiHCan+oi0O6ggKlNhIPxQQD94P1Qu7S+ssiQvE/yzF6bDhYRxqRb7t5jGIyQX iAxVvItm+Iw4pcqhZj4ZpEDuyb8GbviwW2E3S76kfhuxgl5f9O855/oEPsFfKZzoWW Bn7yntMtHJCPw== Received: from hysteria.proulx.com (hysteria.proulx.com [192.168.230.119]) by joseki.proulx.com (Postfix) with ESMTP id CF31021150 for ; Wed, 6 May 2020 13:55:47 -0600 (MDT) Received: by hysteria.proulx.com (Postfix, from userid 1000) id C6D672DC8C; Wed, 6 May 2020 13:55:47 -0600 (MDT) Date: Wed, 6 May 2020 13:55:47 -0600 From: Bob Proulx To: freebsd-questions@freebsd.org Subject: Re: redesignde the unix-like system directory Message-ID: <20200506134457056426360@bob.proulx.com> References: <83788746a7d8a802d8af4b582e00827166febd1a.camel@tom.com> <9a387b42-8da5-2968-24ba-754c3e461252@kicp.uchicago.edu> <20200506151230.GI82984@trajan.stk.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 49HS5722MGz46pZ X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=proulx.com header.s=dkim2048 header.b=kxCtuuhk; dmarc=none; spf=pass (mx1.freebsd.org: domain of bob@proulx.com designates 96.88.95.61 as permitted sender) smtp.mailfrom=bob@proulx.com X-Spamd-Result: default: False [-3.03 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; R_DKIM_ALLOW(-0.20)[proulx.com:s=dkim2048]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+a]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-questions@freebsd.org]; TO_DN_NONE(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; RCVD_COUNT_THREE(0.00)[3]; DMARC_NA(0.00)[proulx.com]; DKIM_TRACE(0.00)[proulx.com:+]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:7922, ipnet:96.64.0.0/11, country:US]; IP_SCORE(-0.53)[ipnet: 96.64.0.0/11(-1.96), asn: 7922(-0.64), country: US(-0.05)] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 May 2020 19:55:56 -0000 Tim Daneliuk wrote: > Arne Steinkamm wrote: > > >> /cloud, various cloud applications > > >> /net, network information and server information, etc. > > Looking at a flat layout like this one gives me a feeling, that > > most people forgot that it's a real bad idea to have a > > external mounted directory in the root directory... easy way to make > > a system unresponsive in case of a network problem. > > Can you say a bit more about why this is so? Assume NFS for simplicity. A mount point at the /nfsmount1 directory. Then run "ls -l /". That needs to stat(2) each entry in / and hits /nfsmount1 with stat(2) which if the nfs server is not responding cannot return an answer to the query. A lot of daemons and cron jobs will assume that the file system root and all entries in there are available and will trigger this problem as a byproduct of their operations. I am just describing "ls -l" as the simplest way to trigger the issue. "NFS server not responding." This can be a reason for a system load of hundreds or thousands as process slots fill up with stuck processes blocked waiting for I/O from an unresponsive server. However in the proposal I think the entries I quoted were for use as a subdirectory and not to have a mount point directly in root. > > I keep the traditional filesystem layout +1. I prefer the traditional file system organization. Bob