From owner-freebsd-fs@FreeBSD.ORG Thu Oct 10 17:16:49 2013 Return-Path: Delivered-To: freebsd-fs@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 ESMTP id E898F443 for ; Thu, 10 Oct 2013 17:16:48 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-qe0-x229.google.com (mail-qe0-x229.google.com [IPv6:2607:f8b0:400d:c02::229]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id AB1A52C96 for ; Thu, 10 Oct 2013 17:16:48 +0000 (UTC) Received: by mail-qe0-f41.google.com with SMTP id x7so1017995qeu.28 for ; Thu, 10 Oct 2013 10:16:47 -0700 (PDT) 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=QFQzpvhMAQD1kjIqBjnIBuuZQAP8rUQA4zKm8IQd6YM=; b=yoUxYItfO2Z4dGb5dDX8bZSyv8AmlaD5RB7E7fXUVhttJckC14ModiNMxp2OuVHYrc 4sT8zQS8p2ajlq+c7nPm2RwWll/vksGGtIvmYNceRO8Nq59ijbej1tqATDK/d2L/7QdF phGUll/75yHNOv3ITX2YJeyjRrhTZPigJ4m9qqva5VC1IDlP1Z1RmPDoxxOhPInwxI2N 8kfDgYxw0Fma9XhfpabzlDPkCkbj266eW8g1q3DmBtkOEfKo6pgj8SrQwqxW1omJW29a Y5zcHJDrRmVYu9CzCr4AXcbuNFtRkPBlS5ZeX7NUorxa0lVMl/bgkGTuDuQNn40I8+71 0r6w== MIME-Version: 1.0 X-Received: by 10.49.130.132 with SMTP id oe4mr3247501qeb.86.1381425407903; Thu, 10 Oct 2013 10:16:47 -0700 (PDT) Received: by 10.49.39.33 with HTTP; Thu, 10 Oct 2013 10:16:47 -0700 (PDT) In-Reply-To: <20131010170724.GA19751@potato.growveg.org> References: <20131010170724.GA19751@potato.growveg.org> Date: Thu, 10 Oct 2013 10:16:47 -0700 Message-ID: Subject: Re: RAM and zfs and multiple disks From: Freddie Cash To: john@potato.growveg.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: FreeBSD Filesystems X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Oct 2013 17:16:49 -0000 On Thu, Oct 10, 2013 at 10:07 AM, John wr= ote: > I'd like to have zfs on my freebsd desktop. However, > this motherboard can take 8GB RAM, max. > > I'd like to get 2 x4Tb drives. Realistically, do I > need another motherboard? The primary reason to have ZFS > is to guard against bitrot > =E2=80=8B. > I ran ZFS on a 32-bit install of FreeBSD using a 3.0 GHz P4 with only 2 GB of RAM for several years. Started with 4x 160 GB drives in a raidz1 vdev and FreeBSD 8.x with / on UFS on a USB stick. Migrated to 2x 500 GB drives in a mirror vdev and FreeBSD 9.0, still with / on UFS on a USB stick. Migrated to 4x 1.0 TB drives in 2 mirror vdevs and PC-BSD 9.1, with ZFS-on-root (no USB sticks). At this point, I switched to a 64-bit install running on an Athlon-II CPU with 4 GB of RAM. Finally, migrated to "rolling-release" of PC-BSD (which shows as TruOS in uname) based on FreeBSD 9-STABLE (post 9.1) running on a Phenom-II X4 with 8 GB of RAM. Beauty of ZFS snapshots send/recv and boot environments is that I didn't lose any data during any of the migrations, and was able to reconfigure the pool a couple of times. And switch from 32-bit to 64-bit FreeBSD (only saved /home for that one). IOW, you don't need a tonne of RAM to run ZFS. You just need to spend some time tweaking ZFS-related tunables in /boot/loader.conf to guard against lockups due to lack of kmem (really only an issue on a 32-bit system due to kmem fragmentation). And, definitely do NOT enable dedupe on a system with multiple TB of storage unless you have 16+ GB of RAM! Compression is fine (running with lz4 on my home system now; originally was lzjb+gzip). --=20 Freddie Cash fjwcash@gmail.com