From owner-freebsd-geom@FreeBSD.ORG Mon Jan 17 13:47:02 2011 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 43D58106566B for ; Mon, 17 Jan 2011 13:47:02 +0000 (UTC) (envelope-from gcubfg-freebsd-geom@m.gmane.org) Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by mx1.freebsd.org (Postfix) with ESMTP id C3A5B8FC0A for ; Mon, 17 Jan 2011 13:47:01 +0000 (UTC) Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1PepQB-0004oL-Cv for freebsd-geom@freebsd.org; Mon, 17 Jan 2011 14:46:59 +0100 Received: from lara.cc.fer.hr ([161.53.72.113]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 17 Jan 2011 14:46:59 +0100 Received: from ivoras by lara.cc.fer.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 17 Jan 2011 14:46:59 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-geom@freebsd.org From: Ivan Voras Date: Mon, 17 Jan 2011 14:46:46 +0100 Lines: 33 Message-ID: References: <1686083494.20110113182418@serebryakov.spb.ru> <1811347380.20110113213700@serebryakov.spb.ru> <234432652.20110117163922@serebryakov.spb.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: lara.cc.fer.hr User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.2.12) Gecko/20101102 Thunderbird/3.1.6 In-Reply-To: <234432652.20110117163922@serebryakov.spb.ru> X-Enigmail-Version: 1.1.2 Subject: Re: Broken gmirror: why /dev/ufs is empty when geom_mirror is not loaded? X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Jan 2011 13:47:02 -0000 On 17/01/2011 14:39, Lev Serebryakov wrote: > Hello, Ivan. > You wrote 17 января 2011 г., 16:30:43: > >>>> I have mirrored PARTITION (/dev/ad4s1d + /dev/ad6s1d) with UFS with >>>> label on it. This label is shown in /dev/ufs when geom_mirror is >>>> loaded. >>> >>>> When geom_mirror is NOT loaded both ad4s1d and ad6s1d are valid, >>>> complete, clean filesystems, but here is no /dev/ufs entries for them, >>>> and kernel can not mount FSes at all. >>> And even worse: it sees ONE of all FSes and when "geom_mirror" is >>> loaded, it puck up one of components from "/dev/ufs/home" instead of >>> device node and everything hangs up due to loop (?)... >> Yes, gmirror and glabel are known to interact badly because of such edge >> cases - since glabel presents the whole underlying device in pretty much >> the same way as the original device entry, gmirror cannot distinguish >> between the two. You could use the "-h" argument to "gmirror create" to >> get around this. >> Since this is so common and has also bitten me in the past, I wonder if >> some kind of avoidance detection mechanism could be created in gmirror? > > I think, it will be better if geom_label will create ufs/ufsid items > always (even if FS size is smaller that it's container (provider) > size), but create providers only as big as FS itself. It this case > geom_mirror will never see its metadata inside "UFS-based" providers > and geom_label will show FS labels even it it inside mirror when > geom_mirror is not loaded at all. Both problems are solved with one > solution :) Ah but you see - the UFS metadata *does* record the correct file system size - and this size spans the entire container, just like /dev/adXsY etc. - so both glabel and gmirror behave correctly.