From owner-freebsd-hackers Wed Jan 29 15: 6:25 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 B7B3137B401 for ; Wed, 29 Jan 2003 15:06:24 -0800 (PST) Received: from sasami.jurai.net (sasami.jurai.net [66.92.160.223]) by mx1.FreeBSD.org (Postfix) with ESMTP id CFA1B43FA3 for ; Wed, 29 Jan 2003 15:06:23 -0800 (PST) (envelope-from winter@jurai.net) Received: from sasami.jurai.net (sasami.jurai.net [66.92.160.223]) by sasami.jurai.net (8.12.6/8.12.5) with ESMTP id h0TN6KvA032442; Wed, 29 Jan 2003 18:06:21 -0500 (EST) (envelope-from winter@jurai.net) Date: Wed, 29 Jan 2003 18:06:20 -0500 (EST) From: "Matthew N. Dodd" To: David Gilbert Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Network block device. In-Reply-To: <15928.23728.549120.559276@canoe.velocet.net> Message-ID: <20030129180043.S8642@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> <15928.21992.586804.141143@canoe.velocet.net> <20030129173416.U8642@sasami.jurai.net> <15928.23728.549120.559276@canoe.velocet.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 On Wed, 29 Jan 2003, David Gilbert wrote: > it doesn't work that way. the result of NBD is a /dev/nbd0 not a > filesystem. Block 0 of /dev/nbd0 is block 0 of /dev/hda1 (say). nbd > runs as a server on the node with the disk and as a client on the node > using the disk. Yes, you still stripe on the client side... but you > stripe across directly mapped block devices (no NFS involved). So involving NFS isn't really going to make that much of a difference. Likely the NBD will have lower overhead but probably not much. What you really want is SCSI over IP. Anything else is just a hack and not to be trusted. I think that NFS is less of a hack than NBD though. Of course if Linux still suffers from poor NFS performance that might explain why they came up with NBD in the first place. -- | Matthew N. Dodd | '78 Datsun 280Z | '75 Volvo 164E | FreeBSD/NetBSD | | winter@jurai.net | 2 x '84 Volvo 245DL | ix86,sparc,pmax | | http://www.jurai.net/~winter | For Great Justice! | ISO8802.5 4ever | To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message