Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752688AbaKFQs7 (ORCPT ); Thu, 6 Nov 2014 11:48:59 -0500 Received: from mail1.windriver.com ([147.11.146.13]:48101 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278AbaKFQs4 (ORCPT ); Thu, 6 Nov 2014 11:48:56 -0500 Message-ID: <545BA625.40308@windriver.com> Date: Thu, 6 Nov 2014 10:47:33 -0600 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.7.0 MIME-Version: 1.0 To: Jens Axboe , lkml Subject: absurdly high "optimal_io_size" on Seagate SAS disk Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [147.11.119.46] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I'm running a modified 3.4-stable on relatively recent X86 server-class hardware. I recently installed a Seagate ST900MM0026 (900GB 2.5in 10K SAS drive) and it's reporting a value of 4294966784 for optimal_io_size. The other parameters look normal though: /sys/block/sda/queue/hw_sector_size:512 /sys/block/sda/queue/logical_block_size:512 /sys/block/sda/queue/max_segment_size:65536 /sys/block/sda/queue/minimum_io_size:512 /sys/block/sda/queue/optimal_io_size:4294966784 The other drives in the system look more like what I'd expect: /sys/block/sdb/queue/hw_sector_size:512 /sys/block/sdb/queue/logical_block_size:512 /sys/block/sdb/queue/max_segment_size:65536 /sys/block/sdb/queue/minimum_io_size:4096 /sys/block/sdb/queue/optimal_io_size:0 /sys/block/sdb/queue/physical_block_size:4096 /sys/block/sdc/queue/hw_sector_size:512 /sys/block/sdc/queue/logical_block_size:512 /sys/block/sdc/queue/max_segment_size:65536 /sys/block/sdc/queue/minimum_io_size:4096 /sys/block/sdc/queue/optimal_io_size:0 /sys/block/sdc/queue/physical_block_size:4096 According to the manual, the ST900MM0026 has a 512 byte physical sector size. Is this a drive firmware bug? Or a bug in the SAS driver? Or is there a valid reason for a single drive to report such a huge value? Would it make sense for the kernel to do some sort of sanity checking on this value? Chris -- 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/