From owner-freebsd-hackers@FreeBSD.ORG Wed Apr 23 01:45:59 2014 Return-Path: Delivered-To: hackers@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 E25CB85A for ; Wed, 23 Apr 2014 01:45:59 +0000 (UTC) Received: from mail-pd0-x230.google.com (mail-pd0-x230.google.com [IPv6:2607:f8b0:400e:c02::230]) (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 B6132177C for ; Wed, 23 Apr 2014 01:45:59 +0000 (UTC) Received: by mail-pd0-f176.google.com with SMTP id r10so228527pdi.21 for ; Tue, 22 Apr 2014 18:45:59 -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 :content-type; bh=H9JBLx4FceuchFfShVrYr52rU05J8RvOBio2Ri4qTHs=; b=laXt5r7V8xG8IVM+iPqkd45weA6+YwHCrOS59cJmBCDVNdi9zajOIj182NLcUrv+TV F6ePx4Vb3j8RxBkFO0WTIn6vvu87JyWQNIBHTWsqonAIK4GIM7ma8HQRyEWJDak1CeyH 66lVxnm4mxHMF2rt8V7q3+i5JrsI2LtIs+BiurcxdJWidMs+cSq9y8h1UENF1sP7GI5d Pmo5Mfg5UiumMvmOYYVI7vQinTTguF24gc5sDUTmENvOIvRkgIL6KYZiUx4xq9eLZjl6 EHeefEpCvg8M35oqbXMCfHsAGXrcKJBznXB7ngRARFezOSY12oCjLuDe+PSSQqC2p5wi SC4w== MIME-Version: 1.0 X-Received: by 10.68.196.168 with SMTP id in8mr14408501pbc.132.1398217559400; Tue, 22 Apr 2014 18:45:59 -0700 (PDT) Received: by 10.70.55.169 with HTTP; Tue, 22 Apr 2014 18:45:59 -0700 (PDT) In-Reply-To: <20140423010417.GH43976@funkthat.com> References: <5355E9F9.5080401@freebsd.org> <63190425-672D-4A05-AAB0-B19A49EDB739@cryptomonkeys.org> <20140422222525.GR1321@albert.catwhisker.org> <20140423010417.GH43976@funkthat.com> Date: Tue, 22 Apr 2014 20:45:59 -0500 Message-ID: Subject: Re: Pointer to info on migrating from UFS2 -> ZFS? From: Adam Vande More To: Adam Vande More , David Wolfskill , Louis Kowolowski , hackers@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.17 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Apr 2014 01:45:59 -0000 On Tue, Apr 22, 2014 at 8:04 PM, John-Mark Gurney wrote: > Adam Vande More wrote this message on Tue, Apr 22, 2014 at 19:50 -0500: > > On Tue, Apr 22, 2014 at 5:25 PM, David Wolfskill >wrote: > > > > > I appreciate the responses, but I seem to have failed to communicate at > > > least a couple of fairly important aspects of what I'm trying to do. > > > So.... > > > > > > On Mon, Apr 21, 2014 at 06:40:05PM -0700, Louis Kowolowski wrote: > > > > I?d probably suggest a couple things: > > > > * VirtualBox (or equiv) for setting up test environments that are > easy > > > to create and destroy. For all the beginning stuff I can think of, you > > > should be able to do just fine with a virtual environment. VMs with a > half > > > dozen virtual disks that are 2G ea come in handy with playing with ZFS. > > > > > > I have existing hardware -- several instantiations of it, including a > > > couple of test machines. I am trying to find out if the use of ZFS > (vs. > > > UFS2+SU) on the existing hardware will provide a performance advantage > > > (and if so, how much, as switching from UFS2 to ZFS is going to be > > > extremely painful). > > > > It's very difficult to make any detailed concise comment since we know > > virtually nothing about your hw or workload. What do you need? More > iops? > > Then use a ZIL (maybe even a battery backed DDR drive) to increase > writes, > > But that is only for sync writes, which are for things like fsync... > ZFS write delays writes for vfs.zfs.txg.timeout seconds and combines > them into transaction groups, so unless you're running a db that does > fsync or an NFS server, a ZIL probably won't help you as much as you > think it will... Obviously benchmark your use case w/ and w/o ZIL... > > > and lots of RAM and cache device to increase read speed. When I had this > > setup, diskinfo run on VM's backed by ZVOL's would reflect SSD, not 7200 > > spinning media speeds. > > > > Also things like transparent compression can help certain workloads > > tremendously. If you're dealing with 99% text data by compressing the > data > > you effectively drastically lower the iops needed to work the data and > > off-load the work to the CPU's which are obvious a lot faster than disk. > > > > There are also a lot of different RAID(z) qualities so care should be > taken > > when choosing layouts. > > Yes, it should be... remeber that raidz is closer to RAID3, than RAID5 > in terms of IOPS, but doesn't suffer the read-modify-write issue that > RAID5 has... So you won't necessarily get the same IOPS from a raidz > config as you would from a hardware raid5 system... > > -- > John-Mark Gurney Voice: +1 415 225 5579 > > "All that I will do, has been done, All that I have, has not." > For even more raid5 fun, check out a "punctured stripe". -- Adam