FW: can i recover an all spare raid10 array ?

[Roland RoLaNd <r_o_l_a_n_d@hotmail.com>]

sending again as it failed to deliver the first time for an 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 19:29:25 +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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