From owner-freebsd-scsi@FreeBSD.ORG Thu Jan 24 21:08:05 2013 Return-Path: Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 08D59D9C; Thu, 24 Jan 2013 21:08:05 +0000 (UTC) (envelope-from daniel@digsys.bg) Received: from smtp-sofia.digsys.bg (smtp-sofia.digsys.bg [193.68.3.230]) by mx1.freebsd.org (Postfix) with ESMTP id 435F2723; Thu, 24 Jan 2013 21:08:03 +0000 (UTC) Received: from digsys200-136.pip.digsys.bg (digsys200-136.pip.digsys.bg [193.68.136.200]) (authenticated bits=0) by smtp-sofia.digsys.bg (8.14.5/8.14.5) with ESMTP id r0OKkb3B079889 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Thu, 24 Jan 2013 22:46:38 +0200 (EET) (envelope-from daniel@digsys.bg) Subject: Re: Problem adding SCSI quirks for a SSD, 4K sector and ZFS Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Content-Type: text/plain; charset=us-ascii From: Daniel Kalchev X-Priority: 3 In-Reply-To: Date: Thu, 24 Jan 2013 22:46:37 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <92BD25C7-FC6C-41AF-80AE-05AAD4CD4659@digsys.bg> References: <492280E6-E3EE-4540-92CE-C535C8943CCF@sarenet.es> To: Borja Marcos X-Mailer: Apple Mail (2.1499) Cc: FreeBSD Filesystems , freebsd-scsi@freebsd.org, Steven Hartland X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Jan 2013 21:08:05 -0000 On Jan 24, 2013, at 6:09 PM, Borja Marcos wrote: > Oh, sorrry for the confusion! I assumed that the da driver would = announce a 4 KB sector instead of the 512 bytes due to the quirks.=20 >=20 > Which brings an interesting question, I might have a potential time = bomb in my experimental machine at home. It's a ZFS mirror with two 500 = MB disks. One of the has 512 byte sectors, the other is "advanced = format".=20 If you did not create your zpool with ashift=3D12, then you have the = bomb already. Disks with different native sector size coexist quite = happily in the same zpool. If the storage does not lie, ZFS will in fact = use the largest 'sector size' and everything will be ok. Many (most) = advanced format drives however lie about their sector size and pretend = to have 512 byte sectors. If you create an zpool with such a drive and = an 'normal' 512 byte drive without explicitly requesting 4k alignment, = thing are bad. Daniel=