From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Philip R. Auld" Subject: Re: [dm-devel] Re: Is there a grand plan for FC failover? Date: Thu, 12 Feb 2004 11:03:02 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20040212110302.G27680@vienna.EGENERA.COM> References: <20040128100236.D11527@vienna.EGENERA.COM> <1075309052.2254.6.camel@mulgrave> <20040128130040.E11527@vienna.EGENERA.COM> <20040128124756.A7232@beaverton.ibm.com> <1075328066.2534.10.camel@mulgrave><20040130194826.GC31596@reti> <20040131115903.A4881@vienna.EGENERA.COM> <20040212101705.F27680@vienna.EGENERA.COM> <1076599721.4442.4.camel@laptop.fenrus.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from roadrunner-base.egenera.com ([63.160.166.46]:33488 "EHLO coyote.egenera.com") by vger.kernel.org with ESMTP id S266334AbUBLQFw (ORCPT ); Thu, 12 Feb 2004 11:05:52 -0500 Content-Disposition: inline In-Reply-To: <1076599721.4442.4.camel@laptop.fenrus.com>; from arjanv@redhat.com on Thu, Feb 12, 2004 at 04:28:41PM +0100 List-Id: linux-scsi@vger.kernel.org To: Arjan van de Ven Cc: SCSI Mailing List Rumor has it that on Thu, Feb 12, 2004 at 04:28:41PM +0100 Arjan van de Ven said: > > > That size is based on the blocksize? Is there a way to set the block size higher than > > 512 w/o mounting it? I've gotten really bad rawio performance on 2.4. since I have a > > limit of 32 sg entries. When Rawio uses a 512 byte blocksize IOs are limited to 16K. > > > > Will this still be a problem in 2.6? > > If you code the driver right, it's not even a problem in 2.4 if you use > a Enterprise Linux distro kernel..... > Hi Arjan, I think you know that I do use your Enterprise kernel :) Can you please explain what "right" means in this case? I've a hardware limit of 32 sg entries. When the blocksize is the default hardware sector size of 512 I get commands of 32 separate 512 bytes scatter-gather entries. This is deteremined at a higher level than my LLDD. What is there that I can do about it in the driver? Cheers, Phil -- Philip R. Auld, Ph.D. Egenera, Inc. Principal Software Engineer 165 Forest St. (508) 858-2628 Marlboro, MA 01752