FW: can i recover an all spare raid10 array ?

[Roland RoLaNd <r_o_l_a_n_d@hotmail.com>]

sending again as it failed the first time for some unknown reason 

________________________________
> From: r_o_l_a_n_d@hotmail.com 
> To: robin@robinhill.me.uk 
> CC: linux-raid@vger.kernel.org 
> Subject: RE: can i recover an all spare raid10 array ? 
> Date: Tue, 28 Oct 2014 19:30:50 +0200 
> 
> 
> Correction: 
> i couldn't force assemble the read devices so i issued instead: 
> 
> mdadm --create /dev/md089 --assume-clean --level=10 --verbose 
> --raid-devices=8 missing /dev/dm-1 /dev/dm-0 /dev/dm-5 /dev/dm-3 
> /dev/dm-2 missing /dev/dm-4 
> 
> which got it into degraded state 
> 
> 
> ________________________________ 
> From: r_o_l_a_n_d@hotmail.com 
> To: robin@robinhill.me.uk 
> CC: linux-raid@vger.kernel.org 
> Subject: RE: can i recover an all spare raid10 array ? 
> Date: Tue, 28 Oct 2014 19:29:25 +0200 
> 
> Thanks for pitching in. 
> here are the responses to you questions: 
> 
> 
> - yes i expected both of them to be part of the array though one of 
> them was just added to the array and didnt finish recovering when raid1 
> "/" crashed 
> 
> - i have not removed their superblocks or at least not in a way that i 
> amaware of 
> 
> - mdadm: 3.2.5-5ubuntu4.1 
> - uname -a: 3.13.0-24-generic 
> 
> 
> PS: 
> I just followed this recovery page: 
> https://raid.wiki.kernel.org/index.php/Recovering_a_failed_software_RAID 
> 
> I managed to reach the last step, whenever i tried to mount it kept 
> asking me for the right file system 
> 
> 
>> Date: Tue, 28 Oct 2014 17:01:11 +0000 
>> From: robin@robinhill.me.uk 
>> To: r_o_l_a_n_d@hotmail.com 
>> CC: linux-raid@vger.kernel.org 
>> Subject: Re: can i recover an all spare raid10 array ? 
>> 
>> On Tue Oct 28, 2014 at 06:22:11PM +0200, Roland RoLaNd wrote: 
>> 
>>> I have two raid arrays on my system: 
>>> raid1: /dev/sdd1 /dev/sdh1 
>>> raid10: /dev/sde1 /dev/sda1 /dev/sdf1 /dec/sdb1 /dev/sdc1 /dev/sdg1 
>>> 
>>> 
>>> two disks had bad sectors: sdd and sdf <<-- they both got hot swapped. 
>>> i added sdf back to raid10 and recovery took place but adding sdd1 to 
>>> raid1 proved to be troublesome 
>>> as i didn't have anything important on '/' i formatted and installed 
>>> ubuntu 14 on raid1 
>>> 
>>> now system is up on raid 1, but raid10 (md127) is inactive 
>>> 
>>> cat /proc/mdstat 
>>> 
>>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] 
> [raid5] [raid4] [raid10] 
>>> md127 : inactive sde1[2](S) sdg1[8](S) sdc1[6](S) sdb1[5](S) 
> sdf1[4](S) sda1[3](S) 
>>> 17580804096 blocks super 1.2 
>>> 
>>> md2 : active raid1 sdh4[0] sdd4[1] 
>>> 2921839424 blocks super 1.2 [2/2] [UU] 
>>> [==>..................] resync = 10.4% 
> (304322368/2921839424) finish=672.5min speed=64861K/sec 
>>> 
>>> md1 : active raid1 sdh3[0] sdd3[1] 
>>> 7996352 blocks super 1.2 [2/2] [UU] 
>>> 
>>> md0 : active raid1 sdh2[0] sdd2[1] 
>>> 292544 blocks super 1.2 [2/2] [UU] 
>>> 
>>> unused devices: <none> 
>>> if i try to assemble md127 
>>> 
>>> 
>>> mdadm --assemble /dev/md127 /dev/sde1 /dev/sda1 /dev/sdf1 
> /dev/sdb1 /dev/sdc1 /dev/sdg1 
>>> mdadm: /dev/sde1 is busy - skipping 
>>> mdadm: /dev/sda1 is busy - skipping 
>>> mdadm: /dev/sdf1 is busy - skipping 
>>> mdadm: /dev/sdb1 is busy - skipping 
>>> mdadm: /dev/sdc1 is busy - skipping 
>>> mdadm: /dev/sdg1 is busy - skipping 
>>> 
>>> 
>>> if i try to add one of the disks: mdadm --add /dev/md127 /dev/sdj1 
>>> mdadm: cannot get array info for /dev/md127 
>>> 
>>> if i try: 
>>> 
>>> mdadm --stop /dev/md127 
>>> mdadm: stopped /dev/md127 
>>> 
>>> then running: mdadm --assemble /dev/md127 /dev/sde1 /dev/sda1 
> /dev/sdf1 /dev/sdb1 /dev/sdc1 /dev/sdg1 
>>> 
>>> returns: 
>>> 
>>> assembled from 5 drives and 1 rebuilding - not enough to start the array 
>>> 
>>> what does it mean ? is my data lost ? 
>>> 
>>> if i examine one of the md127 raid 10 array disks it shows this: 
>>> 
>>> mdadm --examine /dev/sde1 
>>> /dev/sde1: 
>>> Magic : a92b4efc 
>>> Version : 1.2 
>>> Feature Map : 0x0 
>>> Array UUID : ab90d4c8:41a55e14:635025cc:28f0ee76 
>>> Name : ubuntu:data (local to host ubuntu) 
>>> Creation Time : Sat May 10 21:54:56 2014 
>>> Raid Level : raid10 
>>> Raid Devices : 8 
>>> 
>>> Avail Dev Size : 5860268032 (2794.39 GiB 3000.46 GB) 
>>> Array Size : 11720534016 (11177.57 GiB 12001.83 GB) 
>>> Used Dev Size : 5860267008 (2794.39 GiB 3000.46 GB) 
>>> Data Offset : 262144 sectors 
>>> Super Offset : 8 sectors 
>>> State : clean 
>>> Device UUID : a2a5db61:bd79f0ae:99d97f17:21c4a619 
>>> 
>>> Update Time : Tue Oct 28 10:07:18 2014 
>>> Checksum : 409deeb4 - correct 
>>> Events : 8655 
>>> 
>>> Layout : near=2 
>>> Chunk Size : 512K 
>>> 
>>> Device Role : Active device 2 
>>> Array State : AAAAAAAA ('A' == active, '.' == missing) 
>>> 
>>> Used Dev Size : 5860267008 (2794.39 GiB 3000.46 GB) <<--- does this 
> mean i still have my data ? 
>>> 
>>> 
>>> the remaining two disks: 
>>> 
>>> mdadm --examine /dev/sdj1 
>>> mdadm: No md superblock detected on /dev/sdj1. 
>>> mdadm --examine /dev/sdi1 
>>> mdadm: No md superblock detected on /dev/sdi1. 
>> 
>> The --examine output indicates the RAID10 array was 8 members, not 6. 
>> As it stands, you are missing two array members (presumably a mirrored 
>> pair as mdadm won't start the array). Without these you're missing 512K 
>> of every 2M in the array, so your data is toast (well, with a lot of 
>> effort you may recover some files under 1.5M in size). 
>> 
>> Were you expecting sdi1 and sdj1 to have been part of the original 
>> RAID10 array? Have you removed the superblocks from them at any point? 
>> For completeness, what mdadm and kernel versions are you running? 
>> 
>> Cheers, 
>> Robin 
>> -- 
>> ___ 
>> ( ' } | Robin Hill <robin@robinhill.me.uk> | 
>> / / ) | Little Jim says .... | 
>> // !! | "He fallen in de water !!" | 
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