From owner-freebsd-fs@FreeBSD.ORG Wed Nov 19 00:48:55 2008 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DB7A11065672 for ; Wed, 19 Nov 2008 00:48:55 +0000 (UTC) (envelope-from andrew@modulus.org) Received: from secure.kgpl.com (secure.kgpl.com [58.96.21.131]) by mx1.freebsd.org (Postfix) with ESMTP id 925EE8FC16 for ; Wed, 19 Nov 2008 00:48:55 +0000 (UTC) (envelope-from andrew@modulus.org) Received: from secure.kgpl.com (secure.kgpl.com [58.96.21.131]) by localhost.kgpl.com (Postfix) with ESMTP id 00AB737424BD; Wed, 19 Nov 2008 11:30:14 +1100 (EST) X-vFilter: This message has been scanned for viruses by ranger.kgpl.com Received: from [10.1.50.60] (10-1-50-60.admins.kgpn [10.1.50.60]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by secure.kgpl.com (Postfix) with ESMTP id 072CC3742492; Wed, 19 Nov 2008 11:30:12 +1100 (EST) Message-ID: <49235D86.4050106@modulus.org> Date: Wed, 19 Nov 2008 11:27:50 +1100 From: Andrew Snow User-Agent: Thunderbird 2.0.0.14 (X11/20080523) MIME-Version: 1.0 To: Dan , freebsd-fs@freebsd.org References: <20081109174303.GA5146@ourbrains.org> <20081109184349.GG51239@server.vk2pj.dyndns.org> <4920D879.3070806@jrv.org> <20081117050441.GA16855@ourbrains.org> <20081118175210.GA3753@hyperion.scode.org> <20081119001742.GA21835@ourbrains.org> In-Reply-To: <20081119001742.GA21835@ourbrains.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: Re: Will XFS be adopted X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Nov 2008 00:48:55 -0000 Dan wrote: > Has anyone done any bechmarks? Is the cache really helping that much? 1. The downside to the ZFS benefits of instantaneous snapshots, clones, and filesystem-level RAID, is that it has to go through its metadata when you want to search directories or read files. A big cache helps make that faster as the commonly loaded tree nodes are pre-fetched and cached. File data is also pre-fetched, ZFS can handle multiple forward or backward reading streams per open file. 2. Much of the cache is used for writing cache, the more memory that can be thrown at that the more optimised the writing to disk can be. > If > it doesn't, and it performs similarly to other journaling FSes that do > not use this much RAM, well, if it's not waste then what? As I said above, the other filesystems don't give you built-in instant snapshotting and RAID. > Does it guarantee the same atomicity that UFS does? Yes. > Is it OK to run an email server on it? Will I lose messages in cases of powerfail/crash? It is perfect for running email because the transparent compression saves you space and I/O time. However, I would wait until it has been considered stable and moved into the 7-STABLE tree before deploying a production server. - Andrew