From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Jungers Subject: Re: trouble repairing raid10 Date: Thu, 03 Jun 2010 06:38:14 +0200 Message-ID: <4C0731B6.7040701@jungers.net> References: <4C068616.3070703@jungers.net> <20100603101913.3839c934@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100603101913.3839c934@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 06/03/2010 02:19 AM, Neil Brown wrote: > On Wed, 02 Jun 2010 18:25:58 +0200 > Nicolas Jungers wrote: > >> I've a 4 HD raid10 with to failed drive. Any attempt I made to add 2 >> replacement disks fail consistently. >> >> mdadm -Af /dev/md1 /dev/sdm2 /dev/sdp2 /dev/sdb2 /dev/sdd2 >> mdadm: failed to add /dev/sdd2 to /dev/md1: Device or resource busy > > Any idea why sdd2 is busy?? No, because sdd2 is not busy. I have 4 spares (b, c, d and e), the one I set in fourth position in the above mdadm -Af command is reported as busy, whatever the one I set there. The same disk in third position get a mdadm superblock write on them. I suspect then an incorrect error message. >> mdadm: /dev/md1 assembled from 2 drives and 1 spare - not enough to >> start the array. >> >> or >> >> root@disk:~# mdadm -AR /dev/md1 /dev/sdm2 /dev/sdp2 >> mdadm: failed to RUN_ARRAY /dev/md1: Input/output error >> mdadm: Not enough devices to start the array. >> root@disk:~# mdadm --add /dev/md1 /dev/sdb2 >> mdadm: add new device failed for /dev/sdb2 as 4: Invalid argument >> >> >> The array is in near mode and I lost disk 0 and 1. Does it mean that my >> data are toasted? > > Yes. RAID10 can survive the failure of 2 non-adjacent devices and sometimes > 2 adjacent devices. But not 0 and 1 of a near=2 array. > > So if those devices are really dead, so is your data. > > If one of these is actually usable and just had a transient failure then you > could try re-creating the array with the drives, or 'missing' in the right > order and with the write layout/chunksize set. > You would need to be user the 'Data Offset' was the same, which unfortunately > can require using exactly the same version of mdadm as created the array in > the first place. will try that, it was created on a beta of Ubuntu 10.04 and is now running on shipped 10.04 (kernel 2.6.32) > > NeilBrown > >> >> >> >> mdadm --examine /dev/sdm2 >> /dev/sdm2: >> Magic : a92b4efc >> Version : 1.2 >> Feature Map : 0x0 >> Array UUID : d90ad6fe:1355134f:f83ffadc:a4fe7859 >> Name : m1:1 >> Creation Time : Thu Apr 1 21:28:58 2010 >> Raid Level : raid10 >> Raid Devices : 4 >> >> Avail Dev Size : 3907026909 (1863.02 GiB 2000.40 GB) >> Array Size : 7814049792 (3726.03 GiB 4000.79 GB) >> Used Dev Size : 3907024896 (1863.01 GiB 2000.40 GB) >> Data Offset : 272 sectors >> Super Offset : 8 sectors >> State : clean >> Device UUID : e217355e:632ac2f0:8120e55e:3878bd88 >> >> Update Time : Wed Jun 2 12:31:39 2010 >> Checksum : feef2809 - correct >> Events : 1377156 >> >> Layout : near=2, far=1 >> Chunk Size : 1024K >> >> Array Slot : 3 (failed, failed, 2, 3) >> Array State : __uU 2 failed >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html