From owner-freebsd-questions@FreeBSD.ORG Fri Jul 18 17:04:24 2014 Return-Path: Delivered-To: freebsd-questions@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 ESMTPS id DDE60162 for ; Fri, 18 Jul 2014 17:04:23 +0000 (UTC) Received: from mail-wi0-x236.google.com (mail-wi0-x236.google.com [IPv6:2a00:1450:400c:c05::236]) (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 7190728C5 for ; Fri, 18 Jul 2014 17:04:23 +0000 (UTC) Received: by mail-wi0-f182.google.com with SMTP id d1so1160361wiv.9 for ; Fri, 18 Jul 2014 10:04:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=date:from:to:subject:message-id:in-reply-to:references:mime-version :content-type:content-transfer-encoding; bh=GxlvWoVKsLK61dxz+HOC/qoeyDPlM7VJ5aSCjXevo6E=; b=RcBlNBh1DtnmL6xAyFlCAGBtdjwx4MZIb+w5K3w7AS18He0ZWgAa2kbaLVKyLkz+23 kPzYK+WSAQf/t0giOjqtEyLV4CbjSymOrFYcFZmKxur9DeI+6DxChrN3Zf8+LYD3G9JC cSLa1XtvEvq0QO77+CUqLll7wzRldoLGCKv3iDpGB3kaPUAOt/KH4RzFbWfytnfggKwR Wl0T4zMHLWM0aIU+RP0dKhfwdgu2nl2oG1b9HWw5WD1Tphqc9V2cnG9pUYnICOepoTpb 6pDCSJKVbJ+ldNfExnbgW4tNwgobE21nyMv0YKHifuN00M0R/Zf5lo4TZvn1bpr/rVT2 75eA== X-Received: by 10.194.222.230 with SMTP id qp6mr8759041wjc.23.1405703060948; Fri, 18 Jul 2014 10:04:20 -0700 (PDT) Received: from gumby.homeunix.com (4e5670bd.skybroadband.com. [78.86.112.189]) by mx.google.com with ESMTPSA id cj8sm15557711wjb.5.2014.07.18.10.04.19 for (version=SSLv3 cipher=RC4-SHA bits=128/128); Fri, 18 Jul 2014 10:04:20 -0700 (PDT) Date: Fri, 18 Jul 2014 18:04:16 +0100 From: RW To: freebsd-questions@freebsd.org Subject: Re: deciding UFS vs ZFS Message-ID: <20140718180416.715cdc0b@gumby.homeunix.com> In-Reply-To: References: <20140713190308.GA9678@bewilderbeast.blackhelicopters.org> <20140714071443.42f615c5@X220.alogt.com> <53C326EE.1030405@my.hennepintech.edu> <20140714111221.5d4aaea9@X220.alogt.com> <20140715143821.23638db5@gumby.homeunix.com> <20140716143929.74209529@gumby.homeunix.com> X-Mailer: Claws Mail 3.10.1 (GTK+ 2.24.22; amd64-portbld-freebsd10.0) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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: Fri, 18 Jul 2014 17:04:24 -0000 On Fri, 18 Jul 2014 09:48:24 +0100 krad wrote: > "I don't understand why you think that. My point was that losing > random files from everything can be far more disruptive than losing > files from a single mountpoint." > > Well thats why you would use copies=1+n one each dataset that was on a > single drive. That way you wouldnt lose anything. If your that worried > about drive failures though you should be using some kind of raid. Usually the reason someone adds extra drives to a desktop is that they need extra storage. I very much doubt that many people are going to want to keep multiple copies of everything. In any case ZFS isn't guaranteed to be able to keep copies on separate drives. Drive failure is by far the most important source of data loss on Desktops, and with decent journalling (or equivalent), practically the only thing worth worrying about for most people. Data rot will occur, but it's unlikely it will make a difference to desktop data. > "I was really more interested in whether ZFS (with ARC) is faster than > UFS with FreeBSD's own file caching. A lot of people say that putting > an OS on SSD gives a significant speed-up. 16GB should be more than > enough to keep the important system files in memory, so it sounds like > smarter caching might be useful." > > If you want speed sure UFS is faster on the same machine, but thats > because its doing less. Yes, I know ZFS has overheads, but ARC is potentially better than OS caching. The question was whether, with a decent amount memory, ZFS can actually be faster than UFS.