From owner-freebsd-fs@FreeBSD.ORG Sun Feb 21 01:58:25 2010 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DE74B1065676 for ; Sun, 21 Feb 2010 01:58:24 +0000 (UTC) (envelope-from mailinglists@debank.tv) Received: from smtpout01.onlinespamfilter.nl (smtpout01.onlinespamfilter.nl [217.21.240.161]) by mx1.freebsd.org (Postfix) with ESMTP id 6DAD58FC15 for ; Sun, 21 Feb 2010 01:58:24 +0000 (UTC) Received: from smtp.onlinespamfilter.nl (localhost [127.0.0.1]) by smtp.onlinespamfilter.nl (Postfix) with ESMTP id D4F9825079 for ; Sun, 21 Feb 2010 02:58:17 +0100 (CET) Received: from smtp.debank.tv (59-80-ftth.onsneteindhoven.nl [88.159.80.59]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.onlinespamfilter.nl (Postfix) with ESMTP for ; Sun, 21 Feb 2010 02:58:17 +0100 (CET) Received: from smtp.debank.tv (smtp.debank.tv [172.16.143.25]) by smtp.debank.tv (Postfix) with ESMTP id 875F11DB2188 for ; Sun, 21 Feb 2010 02:58:17 +0100 (CET) Received: from jupi.local (121-73-247-214.broadband.telstraclear.net [121.73.247.214]) (using SSLv3 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: rob) by smtp.debank.tv (Postfix) with ESMTPSA id 5F9A01DB2161 for ; Sun, 21 Feb 2010 02:58:16 +0100 (CET) Message-ID: Date: Sun, 21 Feb 2010 14:58:12 +1300 From: mailinglists User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.1.7) Gecko/20100111 Thunderbird/3.0.1 MIME-Version: 1.0 To: freebsd-fs@freebsd.org References: <38989605a696e2cc4c0bf03c2f53e21a, 4B7FD4D2.7040802@andric.com> In-Reply-To: <38989605a696e2cc4c0bf03c2f53e21a,4B7FD4D2.7040802@andric.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP @ debank.tv X-OSF-Virus: CLEAN X-OSF-Outgoing: Innocent X-OSF-SUM: b4381a2bb7edf557d7aafc9bc9537f51 X-OSF-Info: Checked for spam and viruses Subject: Re: zfs on 4k sector disks X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Feb 2010 01:58:25 -0000 On 21/02/10 1:25 AM, Dimitry Andric wrote: > On 2010-02-20 10:47, mailinglists wrote: >> This "Advanced Format" basically means the sectors size on disk is >> changed to 4k in stead of 512k. > > Please note those disks still seem to expose 512B sectors to any OS; the > 4kiB sectors are only used internally. And there seems to be no jumper > to "fix" this behaviour... Unaligned writes can cause multiple > read-write-modify operations, which are most likely bad for performance. > > >> I'm wondering if freeBSD 8.0 using ZFS raidz and drives like these will >> work properly, I've seen a lot of articles and postings about partitions >> not being properly aligned with the physical disk layout and suffering >> big performance hits. My question is; should I worry about these issues >> or does ZFS already align the data on a 4k border? > > You can at least try to make sure your partitions are aligned to 4kiB. > This should be easy enough to do with e.g. gpart(8). I see no specific > alignment options in the zpool(1M) or zfs(1M) manpages, but there may > be some trick that I am not aware of. :) > > With UFS, you might want to experiment with block and fragment sizes, to > see what is most optimal. For example, a block size of 32kiB and > fragment size of 4kiB, on a partition aligned to 4kiB. Dimitry, Thank you for your answer, I won't be bitten by this with the UFS partitions as they reside on a smaller disk with 512b sectors (although I did notice sysinstall still starts at sector 63 when creating ufs partitions which wouldn't work well with the 4k drives). I should probably have been more clear in explaining what I want to achieve setup: FreeBSD 8.0-Stable (RELENG_8) csupped 2 and updated 19 feb 2010. Core2 quad, 4GB mem OS Drive: 500 GB SATA using UFS (defaults from sysinstall) DATA: 3 * 1.5TB ZFS I'd like to setup the ZFS as a raidz using the whole disk, for this to work properly though I guess ZFS should align the start of the FS on a 4k border, I could as a fallback create the ZFS on partitions which start at the right spot but I'd rather stick with the "default" of using the whole drive. Does anybody know how ZFS aligns the FS on disk? Thanks, Rob Evers ***deze e-mail is gescand door Onlinespamfilter.nl***