From owner-svn-src-head@freebsd.org Thu Aug 18 15:02:44 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 169B0BBDD47; Thu, 18 Aug 2016 15:02:44 +0000 (UTC) (envelope-from nwhitehorn@freebsd.org) Received: from d.mail.sonic.net (d.mail.sonic.net [64.142.111.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 0130117C3; Thu, 18 Aug 2016 15:02:43 +0000 (UTC) (envelope-from nwhitehorn@freebsd.org) Received: from zeppelin.tachypleus.net (75-101-50-44.static.sonic.net [75.101.50.44]) (authenticated bits=0) by d.mail.sonic.net (8.15.1/8.15.1) with ESMTPSA id u7IF2cNI031156 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Thu, 18 Aug 2016 08:02:39 -0700 Subject: Re: svn commit: r304142 - head/usr.sbin/bsdinstall/partedit To: =?UTF-8?Q?Dag-Erling_Sm=c3=b8rgrav?= References: <201608150930.u7F9UL1V069576@repo.freebsd.org> <861t1n6749.fsf@desk.des.no> <581c856c-826b-529e-c9c6-a397fb679708@freebsd.org> <86wpjf4eun.fsf@desk.des.no> <8cb3fa1a-50cb-e238-d006-b98a628d446d@freebsd.org> <86k2ff4cxs.fsf@desk.des.no> <86fuq24d8s.fsf@desk.des.no> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org From: Nathan Whitehorn Message-ID: <544c64f4-693a-c5bc-1fb2-e696589583b3@freebsd.org> Date: Thu, 18 Aug 2016 08:02:38 -0700 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <86fuq24d8s.fsf@desk.des.no> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Sonic-CAuth: UmFuZG9tSVZiw3lp/x93PsK+cJvbsJ38gzyLnyx5VDHwJa7dJAXKcGFy+krTGExz0+ktgYwTSfI5BntWbKSgUfvXHyeN6s/fC1a8sPA+GQo= X-Sonic-ID: C;nHnUzVRl5hG3q6/hcgQksw== M;imYmzlRl5hG3q6/hcgQksw== X-Spam-Flag: No X-Sonic-Spam-Details: 0.0/5.0 by cerberusd X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Aug 2016 15:02:44 -0000 On 08/18/16 02:50, Dag-Erling Smørgrav wrote: > Nathan Whitehorn writes: >> OK. In which configurations? My Dell servers, for instance, don't do >> this. How are they set up? What drivers are being used? Is this >> something that affects passthrough disks, RAIDs, disk images? > Most LSI MegaRAID controllers don't have real passthrough, only JBOD. > You can query the drive with "camcontrol identify passX", but the > controller does not report a stripe size for the volume (mfidY). OK, so it's mfid. That's good to know. > >> The point is that *if the reported stripe size is wrong*, more things >> than partition alignment in the installer will suffer for it. > It's not wrong, it's non-existent, and I'm getting really tired of > repeating myself. For some drivers, this interface is not implemented. This is a bug, which should be fixed. > >> Fixing the installer with a bandaid in the run-up to a release is >> fine, but *we need to fix the underlying problem*. > We can't, because hardware sucks, and I'm getting really tired of > repeating myself. > > DES As am I. Here's the point: We have a mechanism (GEOM stripe size) for drivers to supply a default alignment to userland. If we think we can get that right, great. If we don't think we can get it right, the default system policy in the absence of real information from drivers should be modified to report a number that we think is more likely to be safe than the current defaults (the logical sector size, usually 512 bytes) and potentially tunable by the user. Hacking the userland tools one-by-one to impose their own default policies to override the systemwide one is, while a perfectly valid stopgap right before a release, a ridiculous long-term solution. Do you disagree with any of that? -Nathan