From owner-freebsd-hackers Wed Jan 29 14:30: 7 2003 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id F3B8437B401 for ; Wed, 29 Jan 2003 14:30:05 -0800 (PST) Received: from sabre.velocet.net (sabre.velocet.net [216.138.209.205]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2C5F243FA7 for ; Wed, 29 Jan 2003 14:30:05 -0800 (PST) (envelope-from dgilbert@velocet.ca) Received: from trooper.velocet.ca (trooper.velocet.net [216.138.242.2]) by sabre.velocet.net (Postfix) with ESMTP id 48FE81382C9; Wed, 29 Jan 2003 17:30:04 -0500 (EST) Received: by trooper.velocet.ca (Postfix, from userid 66) id 737A77462B; Wed, 29 Jan 2003 17:30:03 -0500 (EST) Received: by canoe.velocet.net (Postfix, from userid 101) id AAD58567628; Wed, 29 Jan 2003 17:30:00 -0500 (EST) From: David Gilbert MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15928.21992.586804.141143@canoe.velocet.net> Date: Wed, 29 Jan 2003 17:30:00 -0500 To: "Matthew N. Dodd" Cc: David Gilbert , freebsd-hackers@FreeBSD.ORG Subject: Re: Network block device. In-Reply-To: <20030129171908.G8642@sasami.jurai.net> References: <15928.6900.948346.474717@canoe.velocet.net> <20030129170512.Y8642@sasami.jurai.net> <15928.21248.483298.203713@canoe.velocet.net> <20030129171908.G8642@sasami.jurai.net> X-Mailer: VM 7.07 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG >>>>> "Matthew" == Matthew N Dodd writes: Matthew> So use vinum, CCD or add the files as swap and make a Matthew> swap-backed filesystem. Matthew> No reason to invent a totally new low level filesystem here. Actually, I can see that working ... but it's going to be a whole lot less efficient than NBD. You're doing block io that gets replicated (say ... raid 1) by vinum and then then turned back into a block transaction by md and then into a network transaction through nfs back to a filesystem transaction on the remote machine (remember md is working on the file) which is then blocked by the remote filesystem. Did I miss anything? As I understand, NBD is just a little driver that lets you mount foo:/dev/ad0s1g over the network and proxies the block transactions across. Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://daveg.ca | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message