[dm-devel] Recover filenames from failed RAID0

Stewart Ives ivessm at softecusa.com
Sun Jul 17 22:56:25 UTC 2016


Michael,

I'll preface my reply with the statement that I am far from an expert at
this but I can read and understand the descriptions of the different RAID
levels and it seems to me with a RAID0 you are SOL if you lose a device in
the array. Just by the very nature of the RAID0 configuration there is
absolutely NO redundancy. The only reason anyone would configure such a
system is for SPEED and the only data that should be permitted on a RAID0
array is temp or working data that is recoverable by other means in the
event of a failure. I know of many Videographers that use a SSD RAID0 array
for working on their current project but they also copy that array out
about every hour for backup.

I pose only one question to you. Did you have a backup?

Good luck.

-stew


>>
>> Stewart M. Ives
>> SofTEC USA
>> 1717 Bridge St
>> New Cumberland, PA 17070 USA
>>
>> Tel: 717-910-4600
>> Fax: 888-371-6022
>> Skype: softecusa-ivessm
>> EMail: ivessm at softecusa.com
>> WebSite: www.softecusa.com
>>

On Sun, Jul 17, 2016 at 3:10 PM, Michel Dubois <michel.dubois.mtl at gmail.com>
wrote:

> Dear linux-raid mailing list,
>
> I have a RAID0 array of four 3TB disks that failed on the "third" disk.
>
> I am aware of the non-redundancy of RAID0 but I would like to recover
> the filenames from that RAID0. If I could recover some data it would
> be a bonus.
>
> Below you'll find the outputs of the following commands
>  mdadm --examine /dev/sd[abcd]1
>  fdisk -l
>
> where sda1, sdb1, sdc1 and sdd1 should be the 4 RAID devices.
>
> What could be my next step?
>
> I thank you for your time
>
> Michel Dubois
>
> ======================
> mdadm --examine /dev/sd[abcd]1
> /dev/sda1:
>           Magic : a92b4efc
>         Version : 00.90.00
>            UUID : 7d247a6e:7b5d46c8:f52d9c89:db304b21
>   Creation Time : Mon Apr 23 19:55:36 2012
>      Raid Level : raid1
>   Used Dev Size : 20980800 (20.01 GiB 21.48 GB)
>      Array Size : 20980800 (20.01 GiB 21.48 GB)
>    Raid Devices : 4
>   Total Devices : 3
> Preferred Minor : 0
>
>     Update Time : Mon Jun 27 21:12:23 2016
>           State : clean
>  Active Devices : 3
> Working Devices : 3
>  Failed Devices : 1
>   Spare Devices : 0
>        Checksum : 1a57db60 - correct
>          Events : 164275
>
>
>       Number   Major   Minor   RaidDevice State
> this     0       8        1        0      active sync   /dev/sda1
>
>    0     0       8        1        0      active sync   /dev/sda1
>    1     1       8       17        1      active sync   /dev/sdb1
>    2     2       0        0        2      faulty removed
>    3     3       8       33        3      active sync   /dev/sdc1
> /dev/sdb1:
>           Magic : a92b4efc
>         Version : 00.90.00
>            UUID : 7d247a6e:7b5d46c8:f52d9c89:db304b21
>   Creation Time : Mon Apr 23 19:55:36 2012
>      Raid Level : raid1
>   Used Dev Size : 20980800 (20.01 GiB 21.48 GB)
>      Array Size : 20980800 (20.01 GiB 21.48 GB)
>    Raid Devices : 4
>   Total Devices : 3
> Preferred Minor : 0
>
>     Update Time : Mon Jun 27 21:12:23 2016
>           State : clean
>  Active Devices : 3
> Working Devices : 3
>  Failed Devices : 1
>   Spare Devices : 0
>        Checksum : 1a57db72 - correct
>          Events : 164275
>
>
>       Number   Major   Minor   RaidDevice State
> this     1       8       17        1      active sync   /dev/sdb1
>
>    0     0       8        1        0      active sync   /dev/sda1
>    1     1       8       17        1      active sync   /dev/sdb1
>    2     2       0        0        2      faulty removed
>    3     3       8       33        3      active sync   /dev/sdc1
> /dev/sdc1:
>           Magic : a92b4efc
>         Version : 00.90.00
>            UUID : 7d247a6e:7b5d46c8:f52d9c89:db304b21
>   Creation Time : Mon Apr 23 19:55:36 2012
>      Raid Level : raid1
>   Used Dev Size : 20980800 (20.01 GiB 21.48 GB)
>      Array Size : 20980800 (20.01 GiB 21.48 GB)
>    Raid Devices : 4
>   Total Devices : 3
> Preferred Minor : 0
>
>     Update Time : Mon Jun 27 21:12:23 2016
>           State : clean
>  Active Devices : 3
> Working Devices : 3
>  Failed Devices : 1
>   Spare Devices : 0
>        Checksum : 1a57db86 - correct
>          Events : 164275
>
>
>       Number   Major   Minor   RaidDevice State
> this     3       8       33        3      active sync   /dev/sdc1
>
>    0     0       8        1        0      active sync   /dev/sda1
>    1     1       8       17        1      active sync   /dev/sdb1
>    2     2       0        0        2      faulty removed
>    3     3       8       33        3      active sync   /dev/sdc1
>
> ======================
> fdisk -l
>
> WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util
> fdisk doesn't support GPT. Use GNU Parted.
>
>
> Disk /dev/sda: 3000.5 GB, 3000592982016 bytes
> 255 heads, 63 sectors/track, 364801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Disk identifier: 0x03afffbe
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sda1               1      267350  2147483647+  ee  EFI GPT
>
> WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util
> fdisk doesn't support GPT. Use GNU Parted.
>
>
> Disk /dev/sdb: 3000.5 GB, 3000592982016 bytes
> 255 heads, 63 sectors/track, 364801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Disk identifier: 0x142a889c
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdb1               1      267350  2147483647+  ee  EFI GPT
>
> WARNING: GPT (GUID Partition Table) detected on '/dev/sdc'! The util
> fdisk doesn't support GPT. Use GNU Parted.
>
>
> Disk /dev/sdc: 3000.5 GB, 3000592982016 bytes
> 255 heads, 63 sectors/track, 364801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Disk identifier: 0x3daebd50
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1               1      267350  2147483647+  ee  EFI GPT
>
> Disk /dev/md0: 21.4 GB, 21484339200 bytes
> 2 heads, 4 sectors/track, 5245200 cylinders
> Units = cylinders of 8 * 512 = 4096 bytes
> Disk identifier: 0x00000000
>
> Disk /dev/md0 doesn't contain a valid partition table
> --
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