Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750882AbWCXPfW (ORCPT ); Fri, 24 Mar 2006 10:35:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750890AbWCXPfW (ORCPT ); Fri, 24 Mar 2006 10:35:22 -0500 Received: from mail.cs.umn.edu ([128.101.36.202]:59010 "EHLO mail.cs.umn.edu") by vger.kernel.org with ESMTP id S1750874AbWCXPfU (ORCPT ); Fri, 24 Mar 2006 10:35:20 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17444.4455.240044.724257@hound.rchland.ibm.com> Date: Fri, 24 Mar 2006 09:33:59 -0600 To: Jeff Garzik Cc: Arjan van de Ven , Alan Cox , Ian Pratt , Anthony Liguori , Chris Wright , virtualization@lists.osdl.org, xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org, Ian Pratt , ian.pratt@cl.cam.ac.uk, SCSI Mailing List Subject: Re: [RFC PATCH 35/35] Add Xen virtual block device driver. In-Reply-To: <4423F91F.4060007@garzik.org> References: <4421D943.1090804@garzik.org> <1143202673.18986.5.camel@localhost.localdomain> <4423E853.1040707@garzik.org> <4423F60B.6020805@garzik.org> <1143207657.2882.65.camel@laptopd505.fenrus.org> <4423F91F.4060007@garzik.org> X-Mailer: VM 7.19 under Emacs 21.4.1 From: boutcher@cs.umn.edu (Dave C Boutcher) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1771 Lines: 43 Jeff Garzik wrote: >Arjan van de Ven wrote: >> On Fri, 2006-03-24 at 08:37 -0500, Jeff Garzik wrote: >>> Jeff Garzik wrote: >>>> In fact, SCSI should make a few things easier, because the notion of >>>> host+bus topology is already present, and notion of messaging is already >>>> present, so you don't have to recreate that in a Xen block device >>>> infrastructure. >>> Another benefit of SCSI: when an IBM hypervisor in the Linux kernel >>> switched to SCSI, that allowed them to replace several drivers (virt >>> disk, virt cdrom, virt floppy?) with a single virt-SCSI driver. > >> but there's a generic one for that: iSCSI >> so in theory you only need to provide a network driver then ;) > >Talk about lots of overhead :) > >OTOH, I bet that T10 is acting at high speed, right this second, to form >a committee, and multiple sub-committees, to standardize SCSI >transported over XenBus. SXP anyone? :) Actually SRP (which T10 has now stopped working on) fits the bill very nicely. I have to say that moving the IBM virtual drivers from a random collection of unique drivers (viodisk, viotape, viocd) to a single virtual SCSI HBA made life much easier. There is a group (actually, at least two groups) working on SCSI target infrastructures...once that is in place, I would expect we could start hacking a Xen virtual HBA. We looked at iSCSI as a transport (instead of SRP) but we felt that the added complexity made it unlikely that the average human could successfully boot their virtual machine Dave B - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/