From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chandra Seetharaman Subject: Re: [dm-devel] [PATCH 0/4] scsi_dh: Make scsi_dh_activate asynchronous Date: Thu, 22 Oct 2009 09:06:28 -0700 Message-ID: <1256227588.6475.6.camel@chandra-ubuntu> References: <20091021162240.8473.99556.sendpatchset@chandra-ubuntu> <20091022010608.GA10445@infradead.org> Reply-To: sekharan@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:39004 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754090AbZJVQGr (ORCPT ); Thu, 22 Oct 2009 12:06:47 -0400 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by e33.co.us.ibm.com (8.14.3/8.13.1) with ESMTP id n9MG4I71023649 for ; Thu, 22 Oct 2009 10:04:18 -0600 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id n9MG6aPv071222 for ; Thu, 22 Oct 2009 10:06:41 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id n9MG6MJv020970 for ; Thu, 22 Oct 2009 10:06:23 -0600 In-Reply-To: <20091022010608.GA10445@infradead.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: device-mapper development , linux-scsi@vger.kernel.org, michaelc@cs.wisc.edu, Benoit_Arthur@emc.com, Eddie.Williams@steeleye.com Hi Christoph, Thanks for looking into this. Babu (LSI) and I did some testing and found couple of problems. Major one was that moving all luns blindly causes luns to be moved to their non-preferred path against the user's setting, which is a no-no. Here is the email Babu sent on this: http://marc.info/?l=linux-scsi&m=125495712310371&w=2 chandra On Wed, 2009-10-21 at 21:06 -0400, Christoph Hellwig wrote: > On Wed, Oct 21, 2009 at 09:22:40AM -0700, Chandra Seetharaman wrote: > > Hello All, > > > > Currently, device handlers process path activation in series. This leads > > to a lot of time delay when more than 100 luns are involved. For example, > > with lsi rdac 100+ luns take about 12-15 minutes. This was found by Moger > > Babu of LSI. > > So what happened to the suggestion to just switch over per target > instead of per lun? It's the obviously much better way to do, and > unless there are bugs in the hardware preventing it from working it > should be the way to go. > > -- > 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