From owner-freebsd-current Wed Mar 29 2:57:41 2000 Delivered-To: freebsd-current@freebsd.org Received: from trinity.skynet.be (trinity.skynet.be [195.238.2.38]) by hub.freebsd.org (Postfix) with ESMTP id E77D037B9F6 for ; Wed, 29 Mar 2000 02:57:37 -0800 (PST) (envelope-from blk@skynet.be) Received: from [195.238.1.121] (brad.techos.skynet.be [195.238.1.121]) by trinity.skynet.be (Postfix) with ESMTP id BDCF118062; Wed, 29 Mar 2000 12:56:56 +0200 (MET DST) Mime-Version: 1.0 X-Sender: blk@pop.skynet.be Message-Id: In-Reply-To: References: Date: Wed, 29 Mar 2000 12:10:04 +0200 To: mjacob@feral.com, Carl Makin From: Brad Knowles Subject: Re: Dual Pathing to SCSI/FC devices. Cc: current@FreeBSD.ORG Content-Type: text/plain; charset="us-ascii" ; format="flowed" Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG At 9:51 PM -0800 2000/3/28, Matthew Jacob wrote: > What's harder is *how* to use it. There are no particular hooks in FFS to > handle the multiple paths simultaneously with any coherency (for performance > reasons, should you want to do so and could prove that it'd be worthwhile), > nor are there any particular hooks that I'm aware of to do dynamic > multipathing for failover reasons at the volume or device level- if >there were > in FreeBSD, I suspect VINUM in conjunction with a completed DEVVS >might be the > place for them, but that's just random speculation on my part. My personal view is that all of this should be invisible to the higher layers, unless they know the right interfaces to use to go looking for this information. The switch should be made at the CAM SCSI layer, and applications above that don't need to know anything about it. -- These are my opinions -- not to be taken as official Skynet policy ====================================================================== Brad Knowles, || Belgacom Skynet SA/NV Systems Architect, Mail/News/FTP/Proxy Admin || Rue Colonel Bourg, 124 Phone/Fax: +32-2-706.13.11/12.49 || B-1140 Brussels http://www.skynet.be || Belgium To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message