Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932852AbZGPRXr (ORCPT ); Thu, 16 Jul 2009 13:23:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932815AbZGPRXq (ORCPT ); Thu, 16 Jul 2009 13:23:46 -0400 Received: from mail.lang.hm ([64.81.33.126]:45084 "EHLO bifrost.lang.hm" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932514AbZGPRXp (ORCPT ); Thu, 16 Jul 2009 13:23:45 -0400 Date: Thu, 16 Jul 2009 10:23:45 -0700 (PDT) From: david@lang.hm X-X-Sender: dlang@asgard To: Matthew Wilcox cc: linux-kernel , linux-scsi@vger.kernel.org Subject: Re: deterministic scsi order with async scan In-Reply-To: <20090716115703.GQ24310@parisc-linux.org> Message-ID: References: <20090716115703.GQ24310@parisc-linux.org> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1899 Lines: 46 On Thu, 16 Jul 2009, Matthew Wilcox wrote: > On Wed, Jul 15, 2009 at 06:09:22PM -0700, david@lang.hm wrote: >> is there any way to get deterministic device ordering with scsi async >> scanning? >> >> currently (2.6.30) it seems that the various scsi busses are loaded in >> the order that they are detected, which can vary from boot to boot >> depending on how long it takes for the card to initialize. > > I think you're confused. The async scsi scanning was designed to _not_ > move devices around randomly. There are other asynchronous schemes in > the kernel, some of which were not designed with the same care. > > The SCSI async scan can't do much about it if the busses are detected > in a different order. > >> would it be possible to detect the cards/drives, but not register them >> until all the detection is complete so that they can be registered in a >> deterministic order? > > That's exactly how the scsi async scanning works. hmm, in that case how can I troubleshoot why this system is detecting the two different PCI-E cards in different orders on different boots. David Lang >> having two drives on two different controllers swap positions from boot >> to boot makes it very painful. yes I can make an initrd that fixes this >> up in user space by examining each drive and creating links to re-order >> them, but this is a lot of work to fix randomization that can be >> prevented in the first place. >> >> David Lang >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- 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/