From owner-freebsd-hackers@FreeBSD.ORG Sat Oct 11 22:30:57 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3D7E21065697 for ; Sat, 11 Oct 2008 22:30:57 +0000 (UTC) (envelope-from ken@mthelicon.com) Received: from hercules.mthelicon.com (hercules.mthelicon.com [IPv6:2001:49f0:2023::2]) by mx1.freebsd.org (Postfix) with ESMTP id 028458FC16 for ; Sat, 11 Oct 2008 22:30:56 +0000 (UTC) (envelope-from ken@mthelicon.com) Received: from feathers.peganest.com ([IPv6:2001:4d48:ad51:32:21b:21ff:fe1c:3ce]) (authenticated bits=0) by hercules.mthelicon.com (8.14.3/8.14.2) with ESMTP id m9BMUsF9021884 (version=TLSv1/SSLv3 cipher=DHE-DSS-AES256-SHA bits=256 verify=NO) for ; Sat, 11 Oct 2008 22:30:55 GMT (envelope-from ken@mthelicon.com) From: Pegasus Mc Cleaft Organization: Feathers To: freebsd-hackers@freebsd.org Date: Sat, 11 Oct 2008 23:30:53 +0100 User-Agent: KMail/1.10.1 (FreeBSD/7.1-PRERELEASE; KDE/4.1.1; amd64; ; ) References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200810112330.53214.ken@mthelicon.com> Subject: Re: ZFS boot X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Oct 2008 22:30:57 -0000 On Saturday 11 October 2008 21:53:35 Nate Eldredge wrote: > On Sat, 11 Oct 2008, Freddie Cash wrote: > > On 10/11/08, Matthew Dillon wrote: > >> With regards to the traditional BSD partitioning scheme, having a > >> separate /usr, /home, /tmp, etc... there's no reason to do that > >> stuff any more with ZFS (or HAMMER). > > > > As separate partitions, no. As separate filesystems, definitely. > > > > While HAMMER PFSes may not support these things yet, ZFS allows you to > > tailor each filesystem to its purpose. For example, you can enable > > compression on /usr/ports, but have a separate /usr/ports/distfilles > > and /usr/ports/work that aren't compressed. Or /usr/src compressed > > and /usr/obj not. Have a small record (block) size for /usr/src, but > > a larger one for /home. Give each user a separate filesystem for > > their /home/, with separate snapshot policies, quotas, and > > reservations (initial filesystem size). > > All this about ZFS sounds great, and I'd like to try it out, but some of > the bugs, etc, listed at http://wiki.freebsd.org/ZFSKnownProblems are > rather alarming. Even on a personal machine, I don't want these features > at the cost of an unstable system. Is that list still current? I dont know if that list is completely accurate any more, but I can tell you from my own personal experience with ZFS that it has been quite good. I have two servers (one is my test-bed at home) and the other is a production server running mostly mysql at work and I have never experienced the dead-locking problem. > > FWIW, my system is amd64 with 1 G of memory, which the page implies is > insufficient. Is it really? This may be purely subjective, as I have never bench marked the speeds, but when I was first testing zfs on a i386 machine with 1gig ram, I thought the performance was mediocre. However, when I loaded the system on a quad core - core2 with 8 gigs ram, I was quite impressed. I put localized changes in my /boot/loader.conf to give the kernel more breathing room and disabled the prefetch for zfs. #more loader.conf vm.kmem_size_max="1073741824" vm.kmem_size="1073741824" vfs.zfs.prefetch_disable=1 The best advice I can give is for you to find an old machine and test-bed zfs for yourself. I personally have been pleased with it and It has saved my machines data 4 times already (dieing hardware, unexpected power bounces, etc) As a side note, my production machine boots off a dedicated UFS drive (where I also have a slice for the swap). /usr, /var, /var/db and /usr/home are zfs. My test server at home only has /usr/home as zfs. I found it easier for me, when I kill the home machine to just do a reload/rebuild of the OS, rebuild the applications, and rechown/grp the home directories. Peg