From owner-freebsd-stable@freebsd.org Tue Nov 17 08:32:36 2015 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id ECE5DA2E0F4; Tue, 17 Nov 2015 08:32:35 +0000 (UTC) (envelope-from kraduk@gmail.com) Received: from mail-wm0-x231.google.com (mail-wm0-x231.google.com [IPv6:2a00:1450:400c:c09::231]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 81F271061; Tue, 17 Nov 2015 08:32:35 +0000 (UTC) (envelope-from kraduk@gmail.com) Received: by wmvv187 with SMTP id v187so214865460wmv.1; Tue, 17 Nov 2015 00:32:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=js8gPnZ617uyojxHsa6RMFJvhn/HmboCYLYIvFMcRew=; b=EWzuCFqaoIVxWIOW9WQ/MnPyMeSg9HUFedBjygjgyJo8CaJZVQW+5W/XOoGgO5vOs4 cVv9cw1jtsSfsMdMdK4HT5+9mCIuD+ajn3Ez3OvH3MvWeHtuNLFZc1fl54lIRnMF40uL WL/VuoEIyirmTYP+V5618viV5vgEYK/zDB9ncTqT+F1qJUxhIFKuuahnFgsnTXqc83/4 wxtwTm47RQQdURMatb24zumkQGVGKiy9+RcdqIoY5FJAPuehyFPcZCc/1l2MUrcMLPx6 YkH+q9p/yG77FSeoMdayqefvGDKB21a6SpRw9NLetqF61jC81uFS1triw8QMJDtPt73V t6mQ== MIME-Version: 1.0 X-Received: by 10.194.185.173 with SMTP id fd13mr41841837wjc.54.1447749153937; Tue, 17 Nov 2015 00:32:33 -0800 (PST) Received: by 10.28.181.213 with HTTP; Tue, 17 Nov 2015 00:32:33 -0800 (PST) In-Reply-To: <564AE3E0.9060209@quip.cz> References: <5644FF09.9090200@free.de> <56472686.5030301@free.de> <20151114143104.GA41119@in-addr.com> <7710CBCC-E68F-4454-9E29-E50ED1C6B511@sarenet.es> <20151116205734.GM48728@zxy.spb.ru> <878D84A9-4553-413B-ACA4-5ABF499F28C1@punkt.de> <564AE3E0.9060209@quip.cz> Date: Tue, 17 Nov 2015 08:32:33 +0000 Message-ID: Subject: Re: ZFS on labelled partitions From: krad To: Miroslav Lachman <000.fbsd@quip.cz> Cc: "Patrick M. Hausen" , Freddie Cash , freebsd-scsi@freebsd.org, freebsd-stable Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.20 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Nov 2015 08:32:36 -0000 It was a control thing again, if you were using a partition another application could be using the drive on another partition, therefore zfs couldn't guarantee exclusive use of the disk so had to be more careful in the way it operated the drive. I think this meant I went into write through mode like you say. On 17 November 2015 at 08:22, Miroslav Lachman <000.fbsd@quip.cz> wrote: > Patrick M. Hausen wrote on 11/17/2015 09:08: > >> Hi, all, >> >> Am 16.11.2015 um 22:19 schrieb Freddie Cash : >>> >>> =E2=80=8BYou label the disks as they are added to the system the first = time. >>> That >>> way, you always know where each disk is located, and you only deal with >>> the >>> labels. >>> >> >> we do the same for obvious reasons. But I always wonder about the possib= le >> downsides, because ZFS documentation explicitly states: >> >> ZFS operates on raw devices, so it is possible to create a >> storage pool comprised of logical >> volumes, either software or hardware. This configuration is not >> recommended, as ZFS works >> best when it uses raw physical devices. Using logical volumes >> might sacrifice performance, >> reliability, or both, and should be avoided. >> >> (from http://docs.oracle.com/cd/E19253-01/819-5461/gbcik/index.html) >> >> Can anyone shed some lght on why not using raw devices might sacrifice >> performance or reliability? Or is this just outdated folklore? >> > > It was on Solaris but not on FreeBSD. If you were using partitions on > Solaris the drive cache was disabled (or something like that, I am not 10= 0% > sure) > > Miroslav Lachman > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"