From owner-freebsd-questions@FreeBSD.ORG Mon Jan 28 01:37:50 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 3A8C3120 for ; Mon, 28 Jan 2013 01:37:50 +0000 (UTC) (envelope-from FreeBSD@shaneware.biz) Received: from ipmail05.adl6.internode.on.net (ipmail05.adl6.internode.on.net [IPv6:2001:44b8:8060:ff02:300:1:6:5]) by mx1.freebsd.org (Postfix) with ESMTP id 9978C8F for ; Mon, 28 Jan 2013 01:37:49 +0000 (UTC) Received: from ppp247-71.static.internode.on.net (HELO leader.local) ([203.122.247.71]) by ipmail05.adl6.internode.on.net with ESMTP; 28 Jan 2013 12:07:47 +1030 Message-ID: <5105D611.4000506@ShaneWare.Biz> Date: Mon, 28 Jan 2013 12:06:17 +1030 From: Shane Ambler User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: james@mansionfamily.plus.com Subject: Re: ZFS - whole disk or partition or BSD slice? References: <5105BEE4.4030402@mansionfamily.plus.com> In-Reply-To: <5105BEE4.4030402@mansionfamily.plus.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: FreeBSD Mailing List X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 28 Jan 2013 01:37:50 -0000 On 28/01/2013 10:27, james wrote: > I have a 9.1 system with some SATA disks in RAIDZ, upgraded from 9.0. > > The disks are all the same type, and I formatted them for FreeBSD and > put ZFS in a slice covering most of them. > > I have seen suggestions for OpenIndiana etc that it is better to let ZFS > have the whole raw disk and that this can control the way it manages the > disk writeback mode. > > Does this apply to FreeBSD and ZFS too? > > Presumably the disks are currently FreeBSD-specific. If I used raw > disks instead of slices, could I read them from a Solaris system too? I recall reading that using partitions for zfs on FreeBSD was as good as full disks. For a boot zpool we need to at least have a partition for the boot-code and one for zfs preventing the use of a full disk. ZFS is meant to be compatible between different endian systems (x86 and sparc) From what I have read and heard it sounds like zpools are expected be compatible between different OS's as well - as far as zpool versions are compatible - but I do expect it would depend on the partition tables being readable - while full disk usage should work I would also think GPT is compatible. OSX 10.5 (x86 and ppc) included a read-only zfs kext (before Apple canned the project) so it must have been able to read Solaris or FreeBSD created zpools which does indicate a fairly high level of compatibility. I believe the way ZFS marks disks/partitions with the zpool data is so that the zpools can be recognised between systems and controllers - it would be interesting to know if and under what conditions a zpool can be accessed, both between different FreeBSD machines as well as the possibility of reading on a Solaris/Indiana machine. Anyone have the resources to test?