From owner-freebsd-questions@FreeBSD.ORG Mon Jul 21 18:44:57 2014 Return-Path: Delivered-To: questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 71396B83 for ; Mon, 21 Jul 2014 18:44:57 +0000 (UTC) Received: from mail-qg0-f41.google.com (mail-qg0-f41.google.com [209.85.192.41]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 307532677 for ; Mon, 21 Jul 2014 18:44:56 +0000 (UTC) Received: by mail-qg0-f41.google.com with SMTP id q107so5870449qgd.14 for ; Mon, 21 Jul 2014 11:44:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:content-type:mime-version:subject:from :in-reply-to:date:content-transfer-encoding:message-id:references:to; bh=AAfbgprSomYaT/Es1BAA+ydHUH69Hz75apIqwNotpNM=; b=A7aeTb8HdP0GOpKmdCvYsiLgaNFvBREFG7qpWWDxHmJlVH3sBn4wtGYVLSo86aTPlZ eMo5vO5aO2QMNqDIwPSC1ETM9RAJnJGzs3KNsiQHTcPxWczt9qXX/NcJE+G6B9O804UB SiB9OU60VHiJnvXkHu4cgHZU0ecy70IDTI4XtK/9K2DnV6uZGSaM4C52kQuaUGLIpZ0F 8X9HlnZMzv+300KeDyog5MKtcMYFAvz60/qYZE/bVO3+jVQ/PfZwgO42b03ON7xZAnY6 t9PVp/hHGiHXZdAZanZFCQpfUyar+I7n2HYHkbKoPmS81j4nrL2QUYmkpNVMhFfvvlfL MOcg== X-Gm-Message-State: ALoCoQm1wx1k6SOEKwAFIUG7CbFMlhmnoxkz56zTMWMVO1h+Gpdf4NddfUs9Eyb6dp5W61LFtTIi X-Received: by 10.224.87.195 with SMTP id x3mr46822560qal.6.1405968289827; Mon, 21 Jul 2014 11:44:49 -0700 (PDT) Received: from [192.168.2.65] ([96.236.21.80]) by mx.google.com with ESMTPSA id z14sm27180400qaw.7.2014.07.21.11.44.49 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 21 Jul 2014 11:44:49 -0700 (PDT) Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: deciding UFS vs ZFS From: Paul Kraus In-Reply-To: <20140713190308.GA9678@bewilderbeast.blackhelicopters.org> Date: Mon, 21 Jul 2014 14:44:48 -0400 Content-Transfer-Encoding: quoted-printable Message-Id: References: <20140713190308.GA9678@bewilderbeast.blackhelicopters.org> To: questions@freebsd.org X-Mailer: Apple Mail (2.1878.6) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Jul 2014 18:44:57 -0000 On Jul 13, 2014, at 15:03, Michael W. Lucas = wrote: > My virtualization system runs KVM, so I use UFS on VMs. Restoring > ZFS disk images via dd can be problematic. I use ZFS for the host and (generally) UFS on the guests. By using one = ZFS dataset per VM and taking frequent (hourly) snapshots I have an easy = way to roll a VM back to a stable state. > For larger boxes running on real iron, I use ZFS. >=20 > But there's a whole range of conditions between these two. And the way > to fill in the gray spaces is to ask. >=20 > So, how do you decide to use which filesystem? I think this decision tree breaks in a number of ways :-)=20 Desktop vs. Server is the first=85 In my world physical servers get ZFS for all of the various reasons = others have points out, but the biggest is the ensured data integrity. = While not perfect (nothing is), it is much closer than any other open = source solution at this point. I generally do not run FreeBSD as a Desktop (nor OmniOS or SmartOS), so = I don=92t have a strong answer for the Desktop case. Once you go down the Server branch there are more branches=85 Physical vs. Virtual I already stated that I like ZFS on physical hardware. ZFS gives me many = handles to tune (almost too many), between: basic vdev layout and configuration: mirrors, raidz, how many vdevs, = etc. compression: I have seen compression make a 5 fold increase in = performance, I have also seen it reduce performance, it all depends on = your work load, CPU horsepower, and memory bandwidth. dedupe: for certain very specific workloads it can make a huge = improvement, for all the others it generally causes more trouble than it = is worth default block size: this one generates more debate than all of the = others combined, suffice it wo say, test with *your* data and choose = wisely L2ARC and ZIL devices: lots more misinformation out there; mirroring = L2ARC is only occasionally of benefit, ZIL *must* be mirrored, but only = benefits SYNC writes. Know your workload and adjust accordingly. For Virtual systems I have used both (ZFS and UFS) and have had no real = negative (or positive) experiences. Then you get into the Type of Server (be it physical or virtual): End User Mail servers (IMAP, etc.) represent a very different workload = than traditional DB servers, but I still like ZFS for the ease of = management and tune-ability. NOTE: I spent over 10 years managing Solaris systems and storage and ZFS = was a welcome change that greatly simplified storage management =85 at a = cost. I had many more ways to recover a SLVM/UFS filesystem than I do a = ZFS dataset. Part of that is maturity, when ZFS is as old as UFS I=92m = sure it=92ll be there too :-=3D) -- Paul Kraus paul@kraus-haus.org