From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Murphy Subject: Re: raid device gone underneath array Date: Thu, 18 Oct 2012 22:29:40 -0600 Message-ID: References: <50809DC5.60106@websitemanagers.com.au> Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid RAID List-Id: linux-raid.ids On Oct 18, 2012, at 10:03 PM, Chris Dunlop wrote: > On 2012-10-19, Adam Goryachev wrote: >> On 19/10/12 11:01, Marcus Sorensen wrote: >>> I've been using software raid to mirror two devices, and recently one >>> of the drives went AWOL. >>> >>> md1 : active raid1 sdm[0] sdc[1](F) >>> 12884900728 blocks super 1.2 [2/1] [U_] >>> bitmap: 1/96 pages [4KB], 65536KB chunk >>> >>> However, md1 froze, and in looking at the logs I saw this: >>> >>> Oct 18 17:47:48 sys kernel: md: cannot remove active disk sdc from md1 ... >>> Oct 18 17:47:48 sys kernel: md: cannot remove active disk sdc from md1 ... >>> >>> [root(marcus)@sanmirror3-01 ~]# mdadm --manage /dev/md1 --remove /dev/sdc >>> mdadm: cannot find /dev/sdc: No such file or directory >>> >>> /dev/sdc was already gone! The /sys/block was already removed, no >>> reference to it in /proc/scsi/scsi. So md1 was destined to sit there >>> forever. So I rebooted and started up the degraded array. >>> >>> Using kernel 3.6.2 from kernel.org >> >> I've also had this problem, I think the kernel notices the device is >> gone, and removes it before MD notices the problem and removes it from >> the array. I managed to resolve this without a reboot by manually >> creating the device in /dev/sdc1 or whatever, and then doing mdadm >> --manage /dev/md0 --remove /dev/sdc1 > > Or you could simply do: > > mdadm --manage /dev/md1 -r failed That's if md knows it's failed. If the speculation is correct, that the kernel bounced the disk before md determined it was failed, then I think the commands are: mdadm --manage /dev/md1 -f detached mdadm --manage /dev/md1 -r detached Chris Murphy