From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chandra Seetharaman Subject: Re: [PATCH 7/9] scsi_dh: Add support for SDEV_PASSIVE Date: Wed, 27 Feb 2008 17:03:30 -0800 Message-ID: <1204160610.4963.49.camel@linuxchandra> References: <20080124003010.18871.84095.sendpatchset@localhost.localdomain> <20080124003203.18871.52040.sendpatchset@localhost.localdomain> <1202151498.3096.84.camel@localhost.localdomain> <1202156151.13537.14.camel@linuxchandra> <1202156914.3096.112.camel@localhost.localdomain> <1202159970.13537.19.camel@linuxchandra> <20080209124511.GB28967@parisc-linux.org> <1202754466.13537.123.camel@linuxchandra> <20080211191800.GO5299@parisc-linux.org> Reply-To: sekharan@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080211191800.GO5299@parisc-linux.org> Sender: linux-scsi-owner@vger.kernel.org To: Matthew Wilcox Cc: James Bottomley , dm-devel@redhat.com, linux-scsi@vger.kernel.org, Mike Anderson , michaelc@cs.wisc.edu, jens.axboe@oracle.com List-Id: dm-devel.ids On Mon, 2008-02-11 at 12:18 -0700, Matthew Wilcox wrote: > On Mon, Feb 11, 2008 at 10:27:46AM -0800, Chandra Seetharaman wrote: > > On Sat, 2008-02-09 at 05:45 -0700, Matthew Wilcox wrote: > > > On Mon, Feb 04, 2008 at 01:19:30PM -0800, Chandra Seetharaman wrote: > > > > The device does send these error messages currently, but it takes some > > > > time to get the check condition back, which adds up the time to boot > > > > especially when the # of LUNS is huge. > > > > > > > > For example, in my test configuration, I had 40 luns, and the time > > > > difference (with this patch and without it) to boot is 171 seconds and > > > > 1426 seconds. > > > > > > Was that with sync or async SCSI bus scanning? > > > > I didn't change anything, IOW, i did default scanning, which I would > > guess sync ?! > > That would depend on your CONFIG_SCSI_SCAN_ASYNC setting. > > Try booting with 'scsi_mod.scan=async' and without this patch, and see > how long it takes. Hi Matthew, scanning in async mode did not help in reducing the boot time. I even changed the configuration, such that 20 active luns and 20 passive luns are in each path, it still didn't change the time it took to reboot. regards, chandra > -- ---------------------------------------------------------------------- Chandra Seetharaman | Be careful what you choose.... - sekharan@us.ibm.com | .......you may get it. ----------------------------------------------------------------------