From owner-freebsd-stable@FreeBSD.ORG Fri May 16 14:18:52 2014 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 27248E7A for ; Fri, 16 May 2014 14:18:52 +0000 (UTC) Received: from leviathan.boiteameuh.org (leviathan.boiteameuh.org [188.165.231.223]) by mx1.freebsd.org (Postfix) with ESMTP id E603C2395 for ; Fri, 16 May 2014 14:18:51 +0000 (UTC) Received: from [192.168.94.8] (marcellus.villenico.boiteameuh.org [192.168.94.8]) by leviathan.boiteameuh.org (Postfix) with ESMTP id 0508D73B22 for ; Fri, 16 May 2014 16:16:48 +0200 (CEST) Message-ID: <53761E51.9060908@boiteameuh.org> Date: Fri, 16 May 2014 10:18:57 -0400 From: Nicolas Haller User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.5.0 MIME-Version: 1.0 To: freebsd-stable@freebsd.org Subject: Re: gmirror + ZFS issues References: <5376115D.5050704@boiteameuh.org> <53761477.70205@denninger.net> In-Reply-To: <53761477.70205@denninger.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 May 2014 14:18:52 -0000 On 16/05/2014 09:36, Karl Denninger wrote: > > On 5/16/2014 8:23 AM, Nicolas Haller wrote: >> Hello, >> >> I've got a new server and I installed FreeBSD 10 on it. I have a >> problem to create a new zfs pool. The command stalls on IO wait (D >> state / zio->io_cv). >> >> The device for the pool is a 1.7T partition (index 4) of a gmirror >> device. > Why? > > ZFS provides its own mirroring and it is superior, as it checksums each > block and thus does not rely on the drive returning an error to detect > problems. It can also rewrite a bad block (assuming the problem is > transient) and scrub also relies on independent components. > > You're destroying the data integrity advantage that ZFS gives you by > using a gmirror under it. Stop doing that and see if your problem > disappears. > > (In other words it sounds like the problem is real but you shouldn't be > doing that anyway, so it also shouldn't bite you.) > Yes you're right but I have two disks on this server which host my non-zfs root fs. The first 98G partition you show on "gpart show" output is my UFS root fs and I want it mirrored. As I'm not sure it's a good idea to mix gmirror and ZFS mirror on the same drives (What do you think about this?), I let gmirror handle the mirror thing. So, yes, I drop the data integrity advantage, but I keep the flexibility given by pools/datasets, send/receive, compression... It's not so bad :-) -- Nicolas Haller