From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 18 Sep 2001 17:00:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 18 Sep 2001 17:00:12 -0400 Received: from stine.vestdata.no ([195.204.68.10]:64723 "EHLO stine.vestdata.no") by vger.kernel.org with ESMTP id ; Tue, 18 Sep 2001 17:00:02 -0400 Date: Tue, 18 Sep 2001 22:59:52 +0200 From: =?iso-8859-1?Q?Ragnar_Kj=F8rstad?= To: Ingo Molnar , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [patch] multipath RAID personality, 2.4.10-pre9 Message-ID: <20010918225952.D5590@vestdata.no> In-Reply-To: <20010916150806.E1541@turbolinux.com> <20010918203946.A12814@wyvern> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.2.5i In-Reply-To: <20010918203946.A12814@wyvern>; from adrian.bridgett@iname.com on Tue, Sep 18, 2001 at 08:39:46PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 18, 2001 at 08:39:46PM +0100, Adrian Bridgett wrote: > Do you have plans to change this? I know that the SDD software for AIX load > balances between paths (and I think EMC's Powerpaths do for AIX too), DMP > (from Veritas) for Solaris doesn't. > > In fact that brings up another point - which path do you use by default? If > you have the SAN situation where you have a farm of servers each with two FC > cards two two FC switches and then to two ports on a storage array, you > don't want everything going to the first switch. Just picking one path to > use at random would be preferable (unless you want to swap every other > servers cables around). I think the multipath driver would benefit from something like the different modes in the new network bonding driver: * round robin * active backup policy * XOR (Not sure if XOR would be needed for md?) I think some other ideas can be stolen from the bonding driver as well, as the problem is very simular - e.g. the concept of low level drivers (optionally) delivering status information, so md don't have to try and fail to detect a link is down, and the timeout settings. -- Ragnar Kjørstad Big Storage