From owner-freebsd-stable@FreeBSD.ORG Mon Dec 9 16:06:37 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D23C7846 for ; Mon, 9 Dec 2013 16:06:37 +0000 (UTC) Received: from mail-qe0-x235.google.com (mail-qe0-x235.google.com [IPv6:2607:f8b0:400d:c02::235]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 8E8A816A0 for ; Mon, 9 Dec 2013 16:06:37 +0000 (UTC) Received: by mail-qe0-f53.google.com with SMTP id nc12so2908167qeb.26 for ; Mon, 09 Dec 2013 08:06:36 -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=CB7yYjgLOqBCmNHHlVfytIOiKi15BZVTELGGth+5dUo=; b=dNmFaQoGJauBFJ4Y0kL5TJSNqxooGeoEhMpeBrFJUGYYLM4RaCkvrVb9J9NC2yXWlK 1N/WMp8eGPwL2HsWPWQxnLFgRFx8/UWa4sBeDUywy1O0RHkFXZA7hh6COgmGYa64hDYE 6vwF3WtWWil0GPxJx8CIlfAFgyK8aWnJcZc0MY9e/gms5U4oHa+DnC06/l37qBiclTnR pIbpfKspTg0eyb0pKxwah+XRooigYby3tLKtEaiuvV8PleV3JY+LWCkLX6ToWy+c3wOq pvLxhl4wR4NJO3w1fnzHXbgzfxvw6MLXWpqKvCc+AAmvk4b0lUzgT3woevfMC+UJQ1YY 8+gA== MIME-Version: 1.0 X-Received: by 10.49.86.169 with SMTP id q9mr34555496qez.19.1386605196765; Mon, 09 Dec 2013 08:06:36 -0800 (PST) Received: by 10.224.36.137 with HTTP; Mon, 9 Dec 2013 08:06:36 -0800 (PST) In-Reply-To: References: Date: Mon, 9 Dec 2013 16:06:36 +0000 Message-ID: Subject: Re: Does FreeBSD's ZFS reserve 1/64 of the capacity for COW? From: krad To: =?ISO-8859-1?Q?Trond_Endrest=F8l?= Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: FreeBSD stable X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Dec 2013 16:06:37 -0000 I wouldnt really worry about it as you shouldnt be planning to go over 80% capacity on a production pool anyhow, as at some point after that, and way before 100% you will start to get big slowdown on writes, which is more of an issue. On 6 December 2013 12:46, Trond Endrest=F8l < Trond.Endrestol@fagskolen.gjovik.no> wrote: > Hi, > > Today I came across "Becoming a ZFS Ninja Part 1" > http://www.youtube.com/watch?v=3DtPsV_8k-aVU featuring Ben Rockwood who > stated that ZFS reserves 1/64 of the capacity for COW safe-guarding. > Fast forward to 00:49:44. Thus, one should take this fact into account > when planning the storage capacity of your (larger) zpools. > > Does FreeBSD's ZFS also reserve 1/64 of the capacity for COW? > > If it's true, then I guess this should be noted in zpool(8) and in the > Handbook. > > Any comments or insights? > Do you think I should file a PR? > > Have a nice weekend! ;-) > > -- > +-------------------------------+------------------------------------+ > | Vennlig hilsen, | Best regards, | > | Trond Endrest=F8l, | Trond Endrest=F8l, = | > | IT-ansvarlig, | System administrator, | > | Fagskolen Innlandet, | Gj=F8vik Technical College, Norway, | > | tlf. mob. 952 62 567, | Cellular...: +47 952 62 567, | > | sentralbord 61 14 54 00. | Switchboard: +47 61 14 54 00. | > +-------------------------------+------------------------------------+ > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >