From owner-freebsd-questions@FreeBSD.ORG Wed May 27 21:11:02 2015 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 72CB1FCE for ; Wed, 27 May 2015 21:11:02 +0000 (UTC) (envelope-from brandon.wandersee@zoho.com) Received: from sender163-mail.zoho.com (sender1.zohomail.com [74.201.84.158]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 5BC2288A for ; Wed, 27 May 2015 21:11:01 +0000 (UTC) (envelope-from brandon.wandersee@zoho.com) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=date:from:to:subject:message-id:references:mime-version:content-type:in-reply-to:user-agent; b=niI64KKTh+4xFh8pYX8GJSIVjUwJr8FI9xtAWdjk3ell0KcFrfg38NRKL+RXNViTfoOERLvyDVa6 j3rhw5f8TbqfcmkzuPQwVvn4v6upyXMt7a0E0eir9wVVrUbV7Aco Received: from WorkBox.Home (184-100-70-168.mpls.qwest.net [184.100.70.168]) by mx.zohomail.com with SMTPS id 1432761052768877.9075440698607; Wed, 27 May 2015 14:10:52 -0700 (PDT) Date: Wed, 27 May 2015 16:10:50 -0500 From: Brandon Wandersee To: freebsd-questions@freebsd.org Subject: Re: ZFS in a VM? Message-ID: <20150527211050.GA11054@WorkBox.Home> References: <9C96EB4B-A230-4A26-BDC3-067367A61E34@shire.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 May 2015 21:11:02 -0000 On 05/27, Chad Leigh Shire.Net LLC wrote: > > > On May 27, 2015, at 1:41 PM, Jaime Kikpole wrote: > > > > On Wed, May 27, 2015 at 3:39 PM, Chad Leigh Shire.Net LLC > > wrote: > >> I do. I do it not so much for any performance benefits, if any, ZFS offers, but more for data integrity. > > > > Exactly what I was looking for, too. > > > > > >> You need to tune it since the VM based disks are not the same as physical disks. > > > > I'm afraid that I don't understand. Can you explain what you mean by "tune it?" > > There are various kernel “tunables” (aka “kernel state”, settable “variables” in the kernel, see “man sysctl”) that affect ZFS. A lot of tuning "knobs" are described here: http://www.solarisinternals.com/wiki/index.php/ZFS%5FEvil%5FTuning%5FGuide As others have implied/stated, any results you get from a VM (especially after fiddling with tuning) won't accurately reflect anything you'd get from using ZFS on bare metal, and some operations are just out of the question. -- =========================================== :: Brandon Wandersee :: :: brandon.wandersee@zoho.com :: =========================================== "A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools." - Douglas Adams ===========================================