From owner-freebsd-fs@FreeBSD.ORG Fri Aug 13 19:15:55 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 634771065674 for ; Fri, 13 Aug 2010 19:15:55 +0000 (UTC) (envelope-from pjd@garage.freebsd.pl) Received: from mail.garage.freebsd.pl (chello089077043238.chello.pl [89.77.43.238]) by mx1.freebsd.org (Postfix) with ESMTP id 52F388FC16 for ; Fri, 13 Aug 2010 19:15:43 +0000 (UTC) Received: by mail.garage.freebsd.pl (Postfix, from userid 65534) id 8D2C645DF4; Fri, 13 Aug 2010 21:15:41 +0200 (CEST) Received: from localhost (chello089077043238.chello.pl [89.77.43.238]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.garage.freebsd.pl (Postfix) with ESMTP id 256A245E13; Fri, 13 Aug 2010 21:15:36 +0200 (CEST) Date: Fri, 13 Aug 2010 21:15:21 +0200 From: Pawel Jakub Dawidek To: Andriy Bakay Message-ID: <20100813191521.GB2006@garage.freebsd.pl> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1UWUbFP1cBYEclgG" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc X-OS: FreeBSD 9.0-CURRENT amd64 X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on mail.garage.freebsd.pl X-Spam-Level: X-Spam-Status: No, score=-0.6 required=4.5 tests=BAYES_00,RCVD_IN_SORBS_DUL autolearn=no version=3.0.4 Cc: freebsd-fs@freebsd.org Subject: Re: Converting sysinstalled FreeBSD into ZFS-only server. 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: Fri, 13 Aug 2010 19:15:55 -0000 --1UWUbFP1cBYEclgG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Aug 09, 2010 at 04:22:42PM -0400, Andriy Bakay wrote: >=20 > 1. In your post you are using dedicated partition for swap. Did it provide > any advantages versus swap on ZFS volume? There is a good chance to deadlock your system when you have swap based on ZVOL, as to operat on ZVOL ZFS needs to allocate some memory, which you probably don't have much when you're swapping. > 2. You are suggesting to set 'vm_kmem_size' value to 150% of RAM. What > pros. and cons. against following formula: >=20 > vm_kmem_size =3D RAM / 2 > vfs.zfs.arc_max =3D vm_kmem_size - 512M Well, I prefer to have as much address space as I have RAM, when you count VM fragmentation in, 150% should be enough to be able to allocate even entire memory for kernel. Of course it all depends on what you run, etc. This is setting I use and I had no problems with it. > 3. Could you be more verbose about your ZFS layout, what major advantages > it provide against for example the following: > http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot. I found it very interesting > but I need more info. I added some notes why I use and recommend such layout at the end of the post. From my experience the fact that file systems are cheap in ZFS doesn't mean it is to have too many of them. For example I don't like to have all /var/ subdirectories are separate ZFS datasets. There are strong reasons to separate some of them (to turn on compression, for example), but not all of them. Of course if you don't like my reasoning or you have different needs, feel free to use whatever layout you feel fits best for you:) I'm also open to comments on the layout I proposed. I use it for quite a while now and I tried different ones before too, but this one I simply find the best. If our official installer will support creating ZFS-only install, I'll be forcing this layout, so if you think something is _very_ wrong about it, let me know. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --1UWUbFP1cBYEclgG Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (FreeBSD) iEYEARECAAYFAkxlmckACgkQForvXbEpPzTHxgCgh7GpJHcorBoFg8F3Gjq5aMUZ 8qoAoLOJ4qmUK3gOp2Jvz8JIuV509erm =fhOH -----END PGP SIGNATURE----- --1UWUbFP1cBYEclgG--