From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nate Dailey Subject: raid1 narrow_write_error with 4K disks, sd "bad block number requested" messages Date: Wed, 28 Jan 2015 10:29:46 -0500 Message-ID: <54C9006A.2030807@stratus.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from p02c12o148.mxlogic.net ([208.65.145.81]:50823 "EHLO p02c12o148.mxlogic.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760664AbbA2JTg (ORCPT ); Thu, 29 Jan 2015 04:19:36 -0500 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-raid@vger.kernel.org Cc: linux-scsi@vger.kernel.org I'm writing about something that appears to be an issue with raid1's narrow_write_error, particular to non-512-byte-sector disks. Here's what I'm doing: - 2 disk raid1, 4K disks, each connected to a different SAS HBA - mount a filesystem on the raid1, run a test that writes to it - remove one of the SAS HBAs (echo 1 > /sys/bus/pci/devices/0000\:45\:00.0/remove) At this point, writes fail and narrow_write_error breaks them up and retries, one sector at a time. But these are 512-byte sectors, and sd doesn't like it: [ 2645.310517] sd 3:0:1:0: [sde] Bad block number requested [ 2645.310610] sd 3:0:1:0: [sde] Bad block number requested [ 2645.310690] sd 3:0:1:0: [sde] Bad block number requested ... There appears to be no real harm done, but there can be a huge number of these messages in the log. I can avoid this by disabling bad block tracking, but it looks like maybe the superblock's bblog_shift is intended to address this exact issue. However, I don't see a way to change it. Presumably this is something mdadm should be setting up? I don't see bblog_shift ever set to anything other than 0. This is on a RHEL 7.1 kernel, version 3.10.0-221.el7. I took a look at upstream sd and md changes and nothing jumps out at me that would have affected this (but I have not tested to see if the bad block messages do or do not happen on an upstream kernel). I'd appreciate any advice re: how to handle this. Thanks! Nate Dailey Stratus Technologies