From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Pepper Subject: Re: Summary of the Multi-Path BOF at OLS and future directions Date: Thu, 7 Aug 2003 16:54:52 -0700 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20030807165452.A27532@jose.vato.org> References: <1060042082.1985.53.camel@fuzzy> <20030807172028.A13400@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from adsl-64-142-13-48.sonic.net ([64.142.13.48]:58378 "HELO jose.vato.org") by vger.kernel.org with SMTP id S271103AbTHGXys (ORCPT ); Thu, 7 Aug 2003 19:54:48 -0400 Content-Disposition: inline In-Reply-To: <20030807172028.A13400@infradead.org>; from hch@infradead.org on Thu, Aug 07, 2003 at 05:20:28PM +0100 List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: James Bottomley , SCSI Mailing List On Thu 07 Aug at 17:20:28 +0100 hch@infradead.org done said: > > > > 5. Vendor value add for specific devices could be encoded both as > > configuration (udev) pieces and plug-ins to the upper layer multi-path > > driver to activate any proprietary vendor specific configuration options > > that may be needed for specific solutions. > > What are examples of such value add? Personally I'm skeptical that there is much need for plugins, but my employer really wants to find ways to sell software licenses for advanced features with their hardware. They've never defined any advanced features in terms that weren't marketing speak. :| One thing I'm curious about is where non-active-active targets would be manually failed over to their alternate controller (if they aren't able to automatically)? Depending on how config happens, a pluggable interface for path selection (or error recovery path selection) _and_ configuration may be needed to handle controller failover in the right way for these devices. Hopefully this sort of device is going away though as higher end storage features are commoditised. At config time there's obviously a need for vendor specific bits since everybody's doing their inquiry data differently and there's no standard way to know a device is active-active or if not which is the preferred controller for a given lun and whether the device is doing automatic or manual volume transfer on a controller failure. I for one wouldn't want to try maintaining a central list of this stuff if the vendors are willing to do it individually. t. -- ********************************************************* * tpepper@vato dot org * Venimus, Vidimus, * * http://www.vato.org/~tpepper * Dolavimus * *********************************************************