Can't mount /dev/md0 Raid5

Can't mount /dev/md0 Raid5

[Joseba Ibarra]

The md0 is ext4 formated. But now, I can even start the SO when all the 
disk are pluged. One of them is corrupt. It makes an odd sound at the 
starting. However if I unplug that disk the system start fine, however 
no RAID is detected and after assemble it says:


root@grafico:/home/jose# mdadm --detail /dev/md0
/dev/md0:
                  Version : 1.2
       Creation Time : Sat Aug 5 23:10:50 2017
             Raid Level : raid5
      Used Dev Size : 976629760 (931.39 GiB 1000.07 GB)
         Raid Devices : 4
         Total Devices : 3
           Persistence : Superblock is persistent

          Update Time : Thu Sep 21 13:34:35 2017
                      State : active, degraded, Not Started
       Active Devices : 3
    Working Devices : 3
       Failed Devices : 0
       Spare Devices : 0

                   Layout : left-symmetric
           Chunk Size : 512K

                    Name : servidor:0
                     UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
                   Events : 3109

     Number   Major   Minor   RaidDevice State
-       0        0        0      removed
1       8       17        1      active sync   /dev/sdb1
2       8       33        2      active sync   /dev/sdc1
3       8       49        3      active sync   /dev/sdd1


I'm not sure how to continue, since i don't see the RAID. GParted see 
the disks, however doesn't see the md0 and I'm bit scared if I lost the 
data content.


Joseba Ibarra

Re: Can't mount /dev/md0 Raid5

[Rudy Zijlstra]

Hi Joseba,


On 11.10.17 12:25, Joseba Ibarra wrote:
> The md0 is ext4 formated. But now, I can even start the SO when all 
> the disk are pluged. One of them is corrupt. It makes an odd sound at 
> the starting. However if I unplug that disk the system start fine, 
> however no RAID is detected and after assemble it says:
>
>
> root@grafico:/home/jose# mdadm --detail /dev/md0
> /dev/md0:
>                  Version : 1.2
>       Creation Time : Sat Aug 5 23:10:50 2017
>             Raid Level : raid5
>      Used Dev Size : 976629760 (931.39 GiB 1000.07 GB)
>         Raid Devices : 4
>         Total Devices : 3
>           Persistence : Superblock is persistent
>
>          Update Time : Thu Sep 21 13:34:35 2017
>                      State : active, degraded, Not Started
>       Active Devices : 3
>    Working Devices : 3
>       Failed Devices : 0
>       Spare Devices : 0
>
>                   Layout : left-symmetric
>           Chunk Size : 512K
>
>                    Name : servidor:0
>                     UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
>                   Events : 3109
>
>     Number   Major   Minor   RaidDevice State
> -       0        0        0      removed
> 1       8       17        1      active sync   /dev/sdb1
> 2       8       33        2      active sync   /dev/sdc1
> 3       8       49        3      active sync   /dev/sdd1
>
>
> I'm not sure how to continue, since i don't see the RAID. GParted see 
> the disks, however doesn't see the md0 and I'm bit scared if I lost 
> the data content.
>
Let me see if i understand you correctly

- with all 4 disks plugged in, your system does not boot
- with the broken disk unplugged, it boots (and from your description it 
is really broken, no DISK recovery possible unless by specialised company)
- raid does not get assembled during boot, you do a manual assembly?
      -> please provide the command you are using

from the log above, you should be able to do a mount of /dev/md0 which 
would auto-start the raid.

If that works, the next step would be to check the health of the other 
disks. smartctl would be your friend.
Another useful action would be to copy all important data to a backup 
before you add a new disk to replace the failed disk.

Cheers

Rudy

Re: Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Hi Rudy

1- Yes, with all 4 disk plugged in, system does not boot
2- Yes, with the broken disk unplugged, it boots
3 - Yes, raid does not assemble during boot. I assemble manually doing

root@grafico:/home/jose# mdadm --assemble --scan /dev/md0
root@grafico:/home/jose# mdadm --assemble --scan
root@grafico:/home/jose# mdadm --assemble /dev/md0

4 -When I try to mount

   mount /dev/md0 /mnt

mount: wrong file system, bad option, bad superblock in /dev/md0, 
missing codepage or helper program, or other error

     In some cases useful info is found in syslog - try dmesg | tail or 
something like that.

I do dmesg | tail

root@grafico:/mnt# dmesg | tail
[  705.021959] md: pers->run() failed ...
[  849.719439] EXT4-fs (md0): unable to read superblock
[  849.719564] EXT4-fs (md0): unable to read superblock
[  849.719589] EXT4-fs (md0): unable to read superblock
[  849.719616] UDF-fs: error (device md0): udf_read_tagged: read failed, 
block=256, location=256
[  849.719625] UDF-fs: error (device md0): udf_read_tagged: read failed, 
block=512, location=512
[  849.719638] UDF-fs: error (device md0): udf_read_tagged: read failed, 
block=256, location=256
[  849.719642] UDF-fs: error (device md0): udf_read_tagged: read failed, 
block=512, location=512
[  849.719643] UDF-fs: warning (device md0): udf_fill_super: No 
partition found (1)
[  849.719667] isofs_fill_super: bread failed, dev=md0, iso_blknum=16, 
block=32

Thanks a lot for your helping
> Rudy Zijlstra <mailto:rudy@grumpydevil.homelinux.org>
> 11 de octubre de 2017, 12:42
> Hi Joseba,
>
>
>
> Let me see if i understand you correctly
>
> - with all 4 disks plugged in, your system does not boot
> - with the broken disk unplugged, it boots (and from your description 
> it is really broken, no DISK recovery possible unless by specialised 
> company)
> - raid does not get assembled during boot, you do a manual assembly?
>      -> please provide the command you are using
>
> from the log above, you should be able to do a mount of /dev/md0 which 
> would auto-start the raid.
>
> If that works, the next step would be to check the health of the other 
> disks. smartctl would be your friend.
> Another useful action would be to copy all important data to a backup 
> before you add a new disk to replace the failed disk.
>
> Cheers
>
> Rudy

Re: Can't mount /dev/md0 Raid5

[Adam Goryachev]

Hi Rudy,

Please send the output of all of the following commands:

cat /proc/mdstat

mdadm --manage /dev/md0 --stop

mdadm --assemble /dev/md0 /dev/sd[bcd]1

cat /proc/mdstat

mdadm --manage /dev/md0 --run

mdadm --manage /dev/md0 --readwrite

cat /proc/mdstat


Basically the above is just looking at what the system has done 
currently, stopping/clearing that, and then trying to assemble it again, 
finally, we try to start it, even if it has one faulty disk.

At this stage, chances look good for recovering all your data, though I 
would advise to get yourself a replacement disk for the dead one so that 
you can restore redundancy as soon as possible.

Regards,Adam



On 11/10/17 22:14, Joseba Ibarra wrote:
> Hi Rudy
>
> 1- Yes, with all 4 disk plugged in, system does not boot
> 2- Yes, with the broken disk unplugged, it boots
> 3 - Yes, raid does not assemble during boot. I assemble manually doing
>
> root@grafico:/home/jose# mdadm --assemble --scan /dev/md0
> root@grafico:/home/jose# mdadm --assemble --scan
> root@grafico:/home/jose# mdadm --assemble /dev/md0
>
> 4 -When I try to mount
>
>   mount /dev/md0 /mnt
>
> mount: wrong file system, bad option, bad superblock in /dev/md0, 
> missing codepage or helper program, or other error
>
>     In some cases useful info is found in syslog - try dmesg | tail or 
> something like that.
>
> I do dmesg | tail
>
> root@grafico:/mnt# dmesg | tail
> [  705.021959] md: pers->run() failed ...
> [  849.719439] EXT4-fs (md0): unable to read superblock
> [  849.719564] EXT4-fs (md0): unable to read superblock
> [  849.719589] EXT4-fs (md0): unable to read superblock
> [  849.719616] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=256, location=256
> [  849.719625] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=512, location=512
> [  849.719638] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=256, location=256
> [  849.719642] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=512, location=512
> [  849.719643] UDF-fs: warning (device md0): udf_fill_super: No 
> partition found (1)
> [  849.719667] isofs_fill_super: bread failed, dev=md0, iso_blknum=16, 
> block=32
>
> Thanks a lot for your helping
>> Rudy Zijlstra <mailto:rudy@grumpydevil.homelinux.org>
>> 11 de octubre de 2017, 12:42
>> Hi Joseba,
>>
>>
>>
>> Let me see if i understand you correctly
>>
>> - with all 4 disks plugged in, your system does not boot
>> - with the broken disk unplugged, it boots (and from your description 
>> it is really broken, no DISK recovery possible unless by specialised 
>> company)
>> - raid does not get assembled during boot, you do a manual assembly?
>>      -> please provide the command you are using
>>
>> from the log above, you should be able to do a mount of /dev/md0 
>> which would auto-start the raid.
>>
>> If that works, the next step would be to check the health of the 
>> other disks. smartctl would be your friend.
>> Another useful action would be to copy all important data to a backup 
>> before you add a new disk to replace the failed disk.
>>
>> Cheers
>>
>> Rudy
> -- 
> 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

-- 
Adam Goryachev
Website Managers
P: +61 2 8304 0000                    adam@websitemanagers.com.au
F: +61 2 8304 0001                     www.websitemanagers.com.au

Re: Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Hi Adam

root@grafico:/mnt# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
[raid4] [raid10]
md0 : inactive sdd1[3] sdb1[1] sdc1[2]
       2929889280 blocks super 1.2

unused devices: <none>


root@grafico:/mnt# mdadm --manage /dev/md0 --stop
mdadm: stopped /dev/md0


root@grafico:/mnt# mdadm --assemble /dev/md0 /dev/sd[bcd]1
mdadm: /dev/md0 assembled from 3 drives - not enough to start the array 
while not clean - consider --force.



root@grafico:/mnt# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
[raid4] [raid10]
unused devices: <none>

At this point I´ve followed the advise using --force

root@grafico:/mnt# mdadm --assemble --force /dev/md0 /dev/sd[bcd]1
mdadm: Marking array /dev/md0 as 'clean'
mdadm: /dev/md0 has been started with 3 drives (out of 4).


root@grafico:/mnt# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
[raid4] [raid10]
md0 : active (auto-read-only) raid5 sdb1[1] sdd1[3] sdc1[2]
       2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
[4/3] [_UUU]
       bitmap: 0/8 pages [0KB], 65536KB chunk

unused devices: <none>


Now I see the RAID, however can't be mounted. So, I'm not sure how to 
backup the data. Gparted shows the partition /dev/md0p1 with the used 
and free space.


If I try

mount /dev/md0 /mnt

again the output is

mount: wrong file system, bad option, bad superblock in /dev/md0, 
missing codepage or helper program, or other error

     In some cases useful info is found in syslog - try dmesg | tail or 
something like that.

I do dmesg | tail

If I try root@grafico:/mnt# mount /dev/md0p1 /mnt
mount: /dev/md0p1: can't read superblock

And


root@grafico:/mnt# dmesg | tail
[ 3263.411724] VFS: Dirty inode writeback failed for block device md0p1 
(err=-5).
[ 3280.486813]  md0: p1
[ 3280.514024]  md0: p1
[ 3452.496811] UDF-fs: warning (device md0): udf_fill_super: No 
partition found (2)
[ 3463.731052] JBD2: Invalid checksum recovering block 630194476 in log
[ 3464.933960] Buffer I/O error on dev md0p1, logical block 630194474, 
lost async page write
[ 3464.933971] Buffer I/O error on dev md0p1, logical block 630194475, 
lost async page write
[ 3465.928066] JBD2: recovery failed
[ 3465.928070] EXT4-fs (md0p1): error loading journal
[ 3465.936852] VFS: Dirty inode writeback failed for block device md0p1 
(err=-5).


Thanks a lot for your time


Joseba Ibarra
> Adam Goryachev <mailto:adam@websitemanagers.com.au>
> 11 de octubre de 2017, 13:29
> Hi Rudy,
>
> Please send the output of all of the following commands:
>
> cat /proc/mdstat
>
> mdadm --manage /dev/md0 --stop
>
> mdadm --assemble /dev/md0 /dev/sd[bcd]1
>
> cat /proc/mdstat
>
> mdadm --manage /dev/md0 --run
>
> mdadm --manage /dev/md0 --readwrite
>
> cat /proc/mdstat
>
>
> Basically the above is just looking at what the system has done 
> currently, stopping/clearing that, and then trying to assemble it 
> again, finally, we try to start it, even if it has one faulty disk.
>
> At this stage, chances look good for recovering all your data, though 
> I would advise to get yourself a replacement disk for the dead one so 
> that you can restore redundancy as soon as possible.
>
> Regards,Adam
>
>

Re: Can't mount /dev/md0 Raid5

[Adam Goryachev]

On 11/10/17 22:56, Joseba Ibarra wrote:
> Hi Adam
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> md0 : inactive sdd1[3] sdb1[1] sdc1[2]
>       2929889280 blocks super 1.2
>
> unused devices: <none>
>
>
> root@grafico:/mnt# mdadm --manage /dev/md0 --stop
> mdadm: stopped /dev/md0
>
>
> root@grafico:/mnt# mdadm --assemble /dev/md0 /dev/sd[bcd]1
> mdadm: /dev/md0 assembled from 3 drives - not enough to start the 
> array while not clean - consider --force.
>
>
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> unused devices: <none>
>
> At this point I´ve followed the advise using --force
>
> root@grafico:/mnt# mdadm --assemble --force /dev/md0 /dev/sd[bcd]1
> mdadm: Marking array /dev/md0 as 'clean'
> mdadm: /dev/md0 has been started with 3 drives (out of 4).
>
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> md0 : active (auto-read-only) raid5 sdb1[1] sdd1[3] sdc1[2]
>       2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
> [4/3] [_UUU]
>       bitmap: 0/8 pages [0KB], 65536KB chunk
>
> unused devices: <none>
>
>
> Now I see the RAID, however can't be mounted. So, I'm not sure how to 
> backup the data. Gparted shows the partition /dev/md0p1 with the used 
> and free space.
>
It still says read-only, can you try:
mdadm --manage /dev/md0 --run
or
mdadm --manage /dev/md0 --readwrite

PS, usually mounting will automatically convert from readonly to 
readwrite, but I recall some cases where this didn't happen for me, so 
it might help you as well.

Regards,
Adam
> Joseba Ibarra
>> Adam Goryachev <mailto:adam@websitemanagers.com.au>
>> 11 de octubre de 2017, 13:29
>> Hi Rudy,
>>
>> Please send the output of all of the following commands:
>>
>> cat /proc/mdstat
>>
>> mdadm --manage /dev/md0 --stop
>>
>> mdadm --assemble /dev/md0 /dev/sd[bcd]1
>>
>> cat /proc/mdstat
>>
>> mdadm --manage /dev/md0 --run
>>
>> mdadm --manage /dev/md0 --readwrite
>>
>> cat /proc/mdstat
>>
>>
>> Basically the above is just looking at what the system has done 
>> currently, stopping/clearing that, and then trying to assemble it 
>> again, finally, we try to start it, even if it has one faulty disk.
>>
>> At this stage, chances look good for recovering all your data, though 
>> I would advise to get yourself a replacement disk for the dead one so 
>> that you can restore redundancy as soon as possible.
>>
>> Regards,Adam
>>
>>
>
> -- 
> 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

Re: Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Still the same. Nothing seems to have changed.


Same answers for mount commands.

Adam Goryachev escribió:
> mdadm --manage /dev/md0 --readwrite 

Jose Ibarra

Re: Can't mount /dev/md0 Raid5

[Adam Goryachev]

What is the output of cat /proc/mdstat after running the readwrite below?

Did you try the --run option?

You need to make sure the array is active/running before you try to 
mount it.

BTW, has anything else happened to the array, other than the drive that 
failed?

Probably should have asked for this before, but what is the full output 
of smartctl for each drive, also mdadm --misc --examine /dev/sd[bcd]1 
(or all three relevant devices)?

Regards,
Adam


On 12/10/17 00:35, Joseba Ibarra wrote:
> Still the same. Nothing seems to have changed.
>
>
> Same answers for mount commands.
>
> Adam Goryachev escribió:
>> mdadm --manage /dev/md0 --readwrite 
>
> Jose Ibarra
> -- 
> 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

Re: Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Hi Adam,

root@grafico:/mnt# mdadm --manage /dev/md0 --readwrite
root@grafico:/mnt# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
[raid4] [raid10]
md0 : active raid5 sdb1[1] sdd1[3] sdc1[2]
       2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
[4/3] [_UUU]
       bitmap: 5/8 pages [20KB], 65536KB chunk

unused devices: <none>


If you mean mdadm --manage /dev/md0 --run I already done and the result 
is the same.

Doing --detail /dev/md0

root@grafico:/mnt# mdadm --detail /dev/md0
/dev/md0:
         Version : 1.2
   Creation Time : Sat Aug  5 23:10:50 2017
      Raid Level : raid5
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
   Used Dev Size : 976629760 (931.39 GiB 1000.07 GB)
    Raid Devices : 4
   Total Devices : 3
     Persistence : Superblock is persistent

   Intent Bitmap : Internal

     Update Time : Wed Oct 11 15:33:13 2017
           State : clean, degraded
  Active Devices : 3
Working Devices : 3
  Failed Devices : 0
   Spare Devices : 0

          Layout : left-symmetric
      Chunk Size : 512K

            Name : servidor:0
            UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
          Events : 3115

     Number   Major   Minor   RaidDevice State
        -       0        0        0      removed
        1       8       17        1      active sync   /dev/sdb1
        2       8       33        2      active sync   /dev/sdc1
        3       8       49        3      active sync   /dev/sdd1


I started the thread with this 
https://marc.info/?l=linux-raid&m=150607163322491&w=2 but after some 
days out cause travel by work I did found the disk stopped working.

I'll give you the current info:

root@grafico:/mnt# fdisk -l

Disco /dev/sdd: 931,5 GiB, 1000204886016 bytes, 1953525168 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 512 bytes / 512 bytes
Tipo de etiqueta de disco: dos
Identificador del disco: 0xa69b0d7f

Disposit.  Inicio Comienzo      Final   Sectores Tamaño Id Tipo
/dev/sdd1             2048 1953523711 1953521664 931,5G fd Linux raid 
autodetect


Disco /dev/sdb: 931,5 GiB, 1000204886016 bytes, 1953525168 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 512 bytes / 512 bytes
Tipo de etiqueta de disco: dos
Identificador del disco: 0x87ea0d19

Disposit.  Inicio Comienzo      Final   Sectores Tamaño Id Tipo
/dev/sdb1             2048 1953523711 1953521664 931,5G fd Linux raid 
autodetect


Disco /dev/sdc: 931,5 GiB, 1000204886016 bytes, 1953525168 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 512 bytes / 512 bytes
Tipo de etiqueta de disco: dos
Identificador del disco: 0x8b48be4a

Disposit.  Inicio Comienzo      Final   Sectores Tamaño Id Tipo
/dev/sdc1             2048 1953523711 1953521664 931,5G fd Linux raid 
autodetect


Disco /dev/md0: 2,7 TiB, 3000206622720 bytes, 5859778560 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 524288 bytes / 1572864 bytes
Tipo de etiqueta de disco: gpt
Identificador del disco: A87C8BBF-5876-4FA6-83F6-46DAF1BDCF75

Disposit.  Comienzo      Final   Sectores Tamaño Tipo
/dev/md0p1     2048 5859776511 5859774464   2,7T Sistema de ficheros de 
Linux

root@grafico:/mnt# mdadm --examine /dev/sdb
/dev/sdb:
    MBR Magic : aa55
Partition[0] :   1953521664 sectors at         2048 (type fd)

root@grafico:/mnt# mdadm --examine /dev/sdc
/dev/sdc:
    MBR Magic : aa55
Partition[0] :   1953521664 sectors at         2048 (type fd)

root@grafico:/mnt# mdadm --examine /dev/sdd
/dev/sdd:
    MBR Magic : aa55
Partition[0] :   1953521664 sectors at                                   2048 (type fd)

root@grafico:/mnt# mdadm --misc --examine /dev/sd[bcd]1
/dev/sdb1:
           Magic : a92b4efc
         Version : 1.2
     Feature Map : 0x1
      Array UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
            Name : servidor:0
   Creation Time : Sat Aug  5 23:10:50 2017
      Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 1953259520 (931.39 GiB 1000.07 GB)
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
     Data Offset : 262144 sectors
    Super Offset : 8 sectors
    Unused Space : before=262056 sectors, after=0 sectors
           State : clean
     Device UUID : 32271db0:38a5220c:c19968af:8fe1a3fb

Internal Bitmap : 8 sectors from superblock
     Update Time : Wed Oct 11 15:33:13 2017
   Bad Block Log : 512 entries available at offset 72 sectors
        Checksum : 86b5e249 - correct
          Events : 3115

          Layout : left-symmetric
      Chunk Size : 512K

    Device Role : Active device 1
    Array State : .AAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdc1:
           Magic : a92b4efc
         Version : 1.2
     Feature Map : 0x1
      Array UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
            Name : servidor:0
   Creation Time : Sat Aug  5 23:10:50 2017
      Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 1953259520 (931.39 GiB 1000.07 GB)
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
     Data Offset : 262144 sectors
    Super Offset : 8 sectors
    Unused Space : before=262056 sectors, after=0 sectors
           State : clean
     Device UUID : 9014cf8b:ea7e22e2:9274be9d:9aeee689

Internal Bitmap : 8 sectors from superblock
     Update Time : Wed Oct 11 15:33:13 2017
   Bad Block Log : 512 entries available at offset 72 sectors
        Checksum : b5009136 - correct
          Events : 3115

          Layout : left-symmetric
      Chunk Size : 512K

    Device Role : Active device 2
    Array State : .AAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd1:
           Magic : a92b4efc
         Version : 1.2
     Feature Map : 0x9
      Array UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
            Name : servidor:0
   Creation Time : Sat Aug  5 23:10:50 2017
      Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 1953259520 (931.39 GiB 1000.07 GB)
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
     Data Offset : 262144 sectors
    Super Offset : 8 sectors
    Unused Space : before=262056 sectors, after=0 sectors
           State : clean
     Device UUID : f95affb4:138bca63:d10df091:1f20af37

Internal Bitmap : 8 sectors from superblock
     Update Time : Wed Oct 11 15:33:13 2017
   Bad Block Log : 512 entries available at offset 72 sectors - bad 
blocks present.
        Checksum : 1d2ae95 - correct
          Events : 3115

          Layout : left-symmetric
      Chunk Size : 512K

    Device Role : Active device 3
    Array State : .AAA ('A' == active, '.' == missing, 'R' == replacing)


The smartctl -a give this log:

root@grafico:/mnt# smartctl -a /dev/sdb
smartctl 6.6 2016-05-31 r4324 [x86_64-linux-4.9.0-3-amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     QEMU HARDDISK
Serial Number:    QM00009
Firmware Version: 2.5+
User Capacity:    1.000.204.886.016 bytes [1,00 TB]
Sector Size:      512 bytes logical/physical
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ATA/ATAPI-7, ATA/ATAPI-5 published, ANSI NCITS 340-2000
Local Time is:    Wed Oct 11 21:42:39 2017 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x82)    Offline data collection activity
                     was completed without error.
                     Auto Offline Data Collection: Enabled.
Self-test execution status:      (   0)    The previous self-test 
routine completed
                     without error or no self-test has ever
                     been run.
Total time to complete Offline
data collection:         (  288) seconds.
Offline data collection
capabilities:              (0x19) SMART execute Offline immediate.
                     No Auto Offline data collection support.
                     Suspend Offline collection upon new
                     command.
                     Offline surface scan supported.
                     Self-test supported.
                     No Conveyance Self-test supported.
                     No Selective Self-test supported.
SMART capabilities:            (0x0003)    Saves SMART data before entering
                     power-saving mode.
                     Supports SMART auto save timer.
Error logging capability:        (0x01)    Error logging supported.
                     No General Purpose Logging support.
Short self-test routine
recommended polling time:      (   2) minutes.
Extended self-test routine
recommended polling time:      (  54) minutes.

SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      
UPDATED  WHEN_FAILED RAW_VALUE
   1 Raw_Read_Error_Rate     0x0003   100   100   006    Pre-fail  
Always       -       0
   3 Spin_Up_Time            0x0003   100   100   000    Pre-fail  
Always       -       16
   4 Start_Stop_Count        0x0002   100   100   020    Old_age   
Always       -       100
   5 Reallocated_Sector_Ct   0x0003   100   100   036    Pre-fail  
Always       -       0
   9 Power_On_Hours          0x0003   100   100   000    Pre-fail  
Always       -       1
  12 Power_Cycle_Count       0x0003   100   100   000    Pre-fail  
Always       -       0
190 Airflow_Temperature_Cel 0x0003   069   069   050    Pre-fail  
Always       -       31 (Min/Max 31/31)

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]

Selective Self-tests/Logging not supported


root@grafico:/mnt# smartctl -a /dev/sdc
smartctl 6.6 2016-05-31 r4324 [x86_64-linux-4.9.0-3-amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     QEMU HARDDISK
Serial Number:    QM00011
Firmware Version: 2.5+
User Capacity:    1.000.204.886.016 bytes [1,00 TB]
Sector Size:      512 bytes logical/physical
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ATA/ATAPI-7, ATA/ATAPI-5 published, ANSI NCITS 340-2000
Local Time is:    Wed Oct 11 21:44:02 2017 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x82)    Offline data collection activity
                     was completed without error.
                     Auto Offline Data Collection: Enabled.
Self-test execution status:      (   0)    The previous self-test 
routine completed
                     without error or no self-test has ever
                     been run.
Total time to complete Offline
data collection:         (  288) seconds.
Offline data collection
capabilities:              (0x19) SMART execute Offline immediate.
                     No Auto Offline data collection support.
                     Suspend Offline collection upon new
                     command.
                     Offline surface scan supported.
                     Self-test supported.
                     No Conveyance Self-test supported.
                     No Selective Self-test supported.
SMART capabilities:            (0x0003)    Saves SMART data before entering
                     power-saving mode.
                     Supports SMART auto save timer.
Error logging capability:        (0x01)    Error logging supported.
                     No General Purpose Logging support.
Short self-test routine
recommended polling time:      (   2) minutes.
Extended self-test routine
recommended polling time:      (  54) minutes.

SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      
UPDATED  WHEN_FAILED RAW_VALUE
   1 Raw_Read_Error_Rate     0x0003   100   100   006    Pre-fail  
Always       -       0
   3 Spin_Up_Time            0x0003   100   100   000    Pre-fail  
Always       -       16
   4 Start_Stop_Count        0x0002   100   100   020    Old_age   
Always       -       100
   5 Reallocated_Sector_Ct   0x0003   100   100   036    Pre-fail  
Always       -       0
   9 Power_On_Hours          0x0003   100   100   000    Pre-fail  
Always       -       1
  12 Power_Cycle_Count       0x0003   100   100   000    Pre-fail  
Always       -       0
190 Airflow_Temperature_Cel 0x0003   069   069   050    Pre-fail  
Always       -       31 (Min/Max 31/31)

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]

Selective Self-tests/Logging not supported


root@grafico:/mnt# smartctl -a /dev/sdd
smartctl 6.6 2016-05-31 r4324 [x86_64-linux-4.9.0-3-amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     QEMU HARDDISK
Serial Number:    QM00013
Firmware Version: 2.5+
User Capacity:    1.000.204.886.016 bytes [1,00 TB]
Sector Size:      512 bytes logical/physical
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ATA/ATAPI-7, ATA/ATAPI-5 published, ANSI NCITS 340-2000
Local Time is:    Wed Oct 11 21:44:24 2017 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x82)    Offline data collection activity
                     was completed without error.
                     Auto Offline Data Collection: Enabled.
Self-test execution status:      (   0)    The previous self-test 
routine completed
                     without error or no self-test has ever
                     been run.
Total time to complete Offline
data collection:         (  288) seconds.
Offline data collection
capabilities:              (0x19) SMART execute Offline immediate.
                     No Auto Offline data collection support.
                     Suspend Offline collection upon new
                     command.
                     Offline surface scan supported.
                     Self-test supported.
                     No Conveyance Self-test supported.
                     No Selective Self-test supported.
SMART capabilities:            (0x0003)    Saves SMART data before entering
                     power-saving mode.
                     Supports SMART auto save timer.
Error logging capability:        (0x01)    Error logging supported.
                     No General Purpose Logging support.
Short self-test routine
recommended polling time:      (   2) minutes.
Extended self-test routine
recommended polling time:      (  54) minutes.

SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      
UPDATED  WHEN_FAILED RAW_VALUE
   1 Raw_Read_Error_Rate     0x0003   100   100   006    Pre-fail  
Always       -       0
   3 Spin_Up_Time            0x0003   100   100   000    Pre-fail  
Always       -       16
   4 Start_Stop_Count        0x0002   100   100   020    Old_age   
Always       -       100
   5 Reallocated_Sector_Ct   0x0003   100   100   036    Pre-fail  
Always       -       0
   9 Power_On_Hours          0x0003   100   100   000    Pre-fail  
Always       -       1
  12 Power_Cycle_Count       0x0003   100   100   000    Pre-fail  
Always       -       0
190 Airflow_Temperature_Cel 0x0003   069   069   050    Pre-fail  
Always       -       31 (Min/Max 31/31)

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]

Selective Self-tests/Logging not supported


In my humble opinioin all these three disks are ok.

Thanks again

Adam Goryachev escribió:
> What is the output of cat /proc/mdstat after running the readwrite below?
>
> Did you try the --run option?
>
> You need to make sure the array is active/running before you try to 
> mount it.
>
> BTW, has anything else happened to the array, other than the drive 
> that failed?
>
> Probably should have asked for this before, but what is the full 
> output of smartctl for each drive, also mdadm --misc --examine 
> /dev/sd[bcd]1 (or all three relevant devices)?
>
> Regards,
> Adam
>
>
> On 12/10/17 00:35, Joseba Ibarra wrote:
>> Still the same. Nothing seems to have changed.
>>
>>
>> Same answers for mount commands.
>>
>> Adam Goryachev escribió:
>>> mdadm --manage /dev/md0 --readwrite 
>>
>> Jose Ibarra
>> -- 
>> 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

-- 
<http://64bits.es/>

Re: Can't mount /dev/md0 Raid5

[Mikael Abrahamsson]

On Wed, 11 Oct 2017, Joseba Ibarra wrote:

> Now I see the RAID, however can't be mounted. So, I'm not sure how to backup 
> the data. Gparted shows the partition /dev/md0p1 with the used and free 
> space.

Do you know what file system you had? Looks like next step is to try to 
run fsck -n (read-only) on md0 and/or md0p1.

What does /etc/fstab contain regarding md0?

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se

Re: Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Hi Mikael,

I had ext4

and for commands:

root@grafico:/mnt# fsck -n /dev/md0
fsck de util-linux 2.29.2
e2fsck 1.43.4 (31-Jan-2017)
ext2fs_open2(): Bad magic number in superblock
fsck.ext2: invalid superblock, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/md0

The superblock could not be read or does not describe a ext2/ext3/ext4 
filesystem.
If the device is invalid and it really contains an ext2/ext3/ext4 filesystem
(and not swap or ufs or something else), then the superblock is corrupt; 
and you might try running e2fsck with an alternate superblock:
     e2fsck -b 8193 <device>
  o
     e2fsck -b 32768 <device>

A gpt partition table is found in /dev/md0


I'm getting more escared....... No idea what to do

Thanks
> Mikael Abrahamsson <mailto:swmike@swm.pp.se>
> 11 de octubre de 2017, 16:01
> On Wed, 11 Oct 2017, Joseba Ibarra wrote:
>
>
> Do you know what file system you had? Looks like next step is to try 
> to run fsck -n (read-only) on md0 and/or md0p1.
>
> What does /etc/fstab contain regarding md0?
>
> Joseba Ibarra <mailto:wajalotnet@gmail.com>
> 11 de octubre de 2017, 13:56
> Hi Adam
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> md0 : inactive sdd1[3] sdb1[1] sdc1[2]
>       2929889280 blocks super 1.2
>
> unused devices: <none>
>
>
> root@grafico:/mnt# mdadm --manage /dev/md0 --stop
> mdadm: stopped /dev/md0
>
>
> root@grafico:/mnt# mdadm --assemble /dev/md0 /dev/sd[bcd]1
> mdadm: /dev/md0 assembled from 3 drives - not enough to start the 
> array while not clean - consider --force.
>
>
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> unused devices: <none>
>
> At this point I´ve followed the advise using --force
>
> root@grafico:/mnt# mdadm --assemble --force /dev/md0 /dev/sd[bcd]1
> mdadm: Marking array /dev/md0 as 'clean'
> mdadm: /dev/md0 has been started with 3 drives (out of 4).
>
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> md0 : active (auto-read-only) raid5 sdb1[1] sdd1[3] sdc1[2]
>       2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
> [4/3] [_UUU]
>       bitmap: 0/8 pages [0KB], 65536KB chunk
>
> unused devices: <none>
>
>
> Now I see the RAID, however can't be mounted. So, I'm not sure how to 
> backup the data. Gparted shows the partition /dev/md0p1 with the used 
> and free space.
>
>
> If I try
>
> mount /dev/md0 /mnt
>
> again the output is
>
> mount: wrong file system, bad option, bad superblock in /dev/md0, 
> missing codepage or helper program, or other error
>
>     In some cases useful info is found in syslog - try dmesg | tail or 
> something like that.
>
> I do dmesg | tail
>
> If I try root@grafico:/mnt# mount /dev/md0p1 /mnt
> mount: /dev/md0p1: can't read superblock
>
> And
>
>
> root@grafico:/mnt# dmesg | tail
> [ 3263.411724] VFS: Dirty inode writeback failed for block device 
> md0p1 (err=-5).
> [ 3280.486813]  md0: p1
> [ 3280.514024]  md0: p1
> [ 3452.496811] UDF-fs: warning (device md0): udf_fill_super: No 
> partition found (2)
> [ 3463.731052] JBD2: Invalid checksum recovering block 630194476 in log
> [ 3464.933960] Buffer I/O error on dev md0p1, logical block 630194474, 
> lost async page write
> [ 3464.933971] Buffer I/O error on dev md0p1, logical block 630194475, 
> lost async page write
> [ 3465.928066] JBD2: recovery failed
> [ 3465.928070] EXT4-fs (md0p1): error loading journal
> [ 3465.936852] VFS: Dirty inode writeback failed for block device 
> md0p1 (err=-5).
>
>
> Thanks a lot for your time
>
>
> Joseba Ibarra
>
> Adam Goryachev <mailto:adam@websitemanagers.com.au>
> 11 de octubre de 2017, 13:29
> Hi Rudy,
>
> Please send the output of all of the following commands:
>
> cat /proc/mdstat
>
> mdadm --manage /dev/md0 --stop
>
> mdadm --assemble /dev/md0 /dev/sd[bcd]1
>
> cat /proc/mdstat
>
> mdadm --manage /dev/md0 --run
>
> mdadm --manage /dev/md0 --readwrite
>
> cat /proc/mdstat
>
>
> Basically the above is just looking at what the system has done 
> currently, stopping/clearing that, and then trying to assemble it 
> again, finally, we try to start it, even if it has one faulty disk.
>
> At this stage, chances look good for recovering all your data, though 
> I would advise to get yourself a replacement disk for the dead one so 
> that you can restore redundancy as soon as possible.
>
> Regards,Adam
>
>
>
>
>
> Joseba Ibarra <mailto:wajalotnet@gmail.com>
> 11 de octubre de 2017, 13:14
> Hi Rudy
>
> 1- Yes, with all 4 disk plugged in, system does not boot
> 2- Yes, with the broken disk unplugged, it boots
> 3 - Yes, raid does not assemble during boot. I assemble manually doing
>
> root@grafico:/home/jose# mdadm --assemble --scan /dev/md0
> root@grafico:/home/jose# mdadm --assemble --scan
> root@grafico:/home/jose# mdadm --assemble /dev/md0
>
> 4 -When I try to mount
>
>   mount /dev/md0 /mnt
>
> mount: wrong file system, bad option, bad superblock in /dev/md0, 
> missing codepage or helper program, or other error
>
>     In some cases useful info is found in syslog - try dmesg | tail or 
> something like that.
>
> I do dmesg | tail
>
> root@grafico:/mnt# dmesg | tail
> [  705.021959] md: pers->run() failed ...
> [  849.719439] EXT4-fs (md0): unable to read superblock
> [  849.719564] EXT4-fs (md0): unable to read superblock
> [  849.719589] EXT4-fs (md0): unable to read superblock
> [  849.719616] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=256, location=256
> [  849.719625] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=512, location=512
> [  849.719638] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=256, location=256
> [  849.719642] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=512, location=512
> [  849.719643] UDF-fs: warning (device md0): udf_fill_super: No 
> partition found (1)
> [  849.719667] isofs_fill_super: bread failed, dev=md0, iso_blknum=16, 
> block=32
>
> Thanks a lot for your helping
> Rudy Zijlstra <mailto:rudy@grumpydevil.homelinux.org>
> 11 de octubre de 2017, 12:42
> Hi Joseba,
>
>
>
> Let me see if i understand you correctly
>
> - with all 4 disks plugged in, your system does not boot
> - with the broken disk unplugged, it boots (and from your description 
> it is really broken, no DISK recovery possible unless by specialised 
> company)
> - raid does not get assembled during boot, you do a manual assembly?
>      -> please provide the command you are using
>
> from the log above, you should be able to do a mount of /dev/md0 which 
> would auto-start the raid.
>
> If that works, the next step would be to check the health of the other 
> disks. smartctl would be your friend.
> Another useful action would be to copy all important data to a backup 
> before you add a new disk to replace the failed disk.
>
> Cheers
>
> Rudy

-- 
<http://64bits.es/>

Re: Can't mount /dev/md0 Raid5

[NeilBrown]

[-- Attachment #1: Type: text/plain, Size: 8002 bytes --]

On Wed, Oct 11 2017, Joseba Ibarra wrote:

> Hi Mikael,
>
> I had ext4
>
> and for commands:
>
> root@grafico:/mnt# fsck -n /dev/md0
> fsck de util-linux 2.29.2
> e2fsck 1.43.4 (31-Jan-2017)
> ext2fs_open2(): Bad magic number in superblock
> fsck.ext2: invalid superblock, trying backup blocks...
> fsck.ext2: Bad magic number in super-block while trying to open /dev/md0
>
> The superblock could not be read or does not describe a ext2/ext3/ext4 
> filesystem.
> If the device is invalid and it really contains an ext2/ext3/ext4 filesystem
> (and not swap or ufs or something else), then the superblock is corrupt; 
> and you might try running e2fsck with an alternate superblock:
>      e2fsck -b 8193 <device>
>   o
>      e2fsck -b 32768 <device>
>
> A gpt partition table is found in /dev/md0


Mikael suggested:

>> try to run fsck -n (read-only) on md0 and/or md0p1.

But you only tried
   fsck -n /dev/md0
why didn't you also try
   fsck -n /dev/md0p1
??

NeilBrown


>
>
> I'm getting more escared....... No idea what to do
>
> Thanks
>> Mikael Abrahamsson <mailto:swmike@swm.pp.se>
>> 11 de octubre de 2017, 16:01
>> On Wed, 11 Oct 2017, Joseba Ibarra wrote:
>>
>>
>> Do you know what file system you had? Looks like next step is to try 
>> to run fsck -n (read-only) on md0 and/or md0p1.
>>
>> What does /etc/fstab contain regarding md0?
>>
>> Joseba Ibarra <mailto:wajalotnet@gmail.com>
>> 11 de octubre de 2017, 13:56
>> Hi Adam
>>
>> root@grafico:/mnt# cat /proc/mdstat
>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
>> [raid4] [raid10]
>> md0 : inactive sdd1[3] sdb1[1] sdc1[2]
>>       2929889280 blocks super 1.2
>>
>> unused devices: <none>
>>
>>
>> root@grafico:/mnt# mdadm --manage /dev/md0 --stop
>> mdadm: stopped /dev/md0
>>
>>
>> root@grafico:/mnt# mdadm --assemble /dev/md0 /dev/sd[bcd]1
>> mdadm: /dev/md0 assembled from 3 drives - not enough to start the 
>> array while not clean - consider --force.
>>
>>
>>
>> root@grafico:/mnt# cat /proc/mdstat
>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
>> [raid4] [raid10]
>> unused devices: <none>
>>
>> At this point I´ve followed the advise using --force
>>
>> root@grafico:/mnt# mdadm --assemble --force /dev/md0 /dev/sd[bcd]1
>> mdadm: Marking array /dev/md0 as 'clean'
>> mdadm: /dev/md0 has been started with 3 drives (out of 4).
>>
>>
>> root@grafico:/mnt# cat /proc/mdstat
>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
>> [raid4] [raid10]
>> md0 : active (auto-read-only) raid5 sdb1[1] sdd1[3] sdc1[2]
>>       2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
>> [4/3] [_UUU]
>>       bitmap: 0/8 pages [0KB], 65536KB chunk
>>
>> unused devices: <none>
>>
>>
>> Now I see the RAID, however can't be mounted. So, I'm not sure how to 
>> backup the data. Gparted shows the partition /dev/md0p1 with the used 
>> and free space.
>>
>>
>> If I try
>>
>> mount /dev/md0 /mnt
>>
>> again the output is
>>
>> mount: wrong file system, bad option, bad superblock in /dev/md0, 
>> missing codepage or helper program, or other error
>>
>>     In some cases useful info is found in syslog - try dmesg | tail or 
>> something like that.
>>
>> I do dmesg | tail
>>
>> If I try root@grafico:/mnt# mount /dev/md0p1 /mnt
>> mount: /dev/md0p1: can't read superblock
>>
>> And
>>
>>
>> root@grafico:/mnt# dmesg | tail
>> [ 3263.411724] VFS: Dirty inode writeback failed for block device 
>> md0p1 (err=-5).
>> [ 3280.486813]  md0: p1
>> [ 3280.514024]  md0: p1
>> [ 3452.496811] UDF-fs: warning (device md0): udf_fill_super: No 
>> partition found (2)
>> [ 3463.731052] JBD2: Invalid checksum recovering block 630194476 in log
>> [ 3464.933960] Buffer I/O error on dev md0p1, logical block 630194474, 
>> lost async page write
>> [ 3464.933971] Buffer I/O error on dev md0p1, logical block 630194475, 
>> lost async page write
>> [ 3465.928066] JBD2: recovery failed
>> [ 3465.928070] EXT4-fs (md0p1): error loading journal
>> [ 3465.936852] VFS: Dirty inode writeback failed for block device 
>> md0p1 (err=-5).
>>
>>
>> Thanks a lot for your time
>>
>>
>> Joseba Ibarra
>>
>> Adam Goryachev <mailto:adam@websitemanagers.com.au>
>> 11 de octubre de 2017, 13:29
>> Hi Rudy,
>>
>> Please send the output of all of the following commands:
>>
>> cat /proc/mdstat
>>
>> mdadm --manage /dev/md0 --stop
>>
>> mdadm --assemble /dev/md0 /dev/sd[bcd]1
>>
>> cat /proc/mdstat
>>
>> mdadm --manage /dev/md0 --run
>>
>> mdadm --manage /dev/md0 --readwrite
>>
>> cat /proc/mdstat
>>
>>
>> Basically the above is just looking at what the system has done 
>> currently, stopping/clearing that, and then trying to assemble it 
>> again, finally, we try to start it, even if it has one faulty disk.
>>
>> At this stage, chances look good for recovering all your data, though 
>> I would advise to get yourself a replacement disk for the dead one so 
>> that you can restore redundancy as soon as possible.
>>
>> Regards,Adam
>>
>>
>>
>>
>>
>> Joseba Ibarra <mailto:wajalotnet@gmail.com>
>> 11 de octubre de 2017, 13:14
>> Hi Rudy
>>
>> 1- Yes, with all 4 disk plugged in, system does not boot
>> 2- Yes, with the broken disk unplugged, it boots
>> 3 - Yes, raid does not assemble during boot. I assemble manually doing
>>
>> root@grafico:/home/jose# mdadm --assemble --scan /dev/md0
>> root@grafico:/home/jose# mdadm --assemble --scan
>> root@grafico:/home/jose# mdadm --assemble /dev/md0
>>
>> 4 -When I try to mount
>>
>>   mount /dev/md0 /mnt
>>
>> mount: wrong file system, bad option, bad superblock in /dev/md0, 
>> missing codepage or helper program, or other error
>>
>>     In some cases useful info is found in syslog - try dmesg | tail or 
>> something like that.
>>
>> I do dmesg | tail
>>
>> root@grafico:/mnt# dmesg | tail
>> [  705.021959] md: pers->run() failed ...
>> [  849.719439] EXT4-fs (md0): unable to read superblock
>> [  849.719564] EXT4-fs (md0): unable to read superblock
>> [  849.719589] EXT4-fs (md0): unable to read superblock
>> [  849.719616] UDF-fs: error (device md0): udf_read_tagged: read 
>> failed, block=256, location=256
>> [  849.719625] UDF-fs: error (device md0): udf_read_tagged: read 
>> failed, block=512, location=512
>> [  849.719638] UDF-fs: error (device md0): udf_read_tagged: read 
>> failed, block=256, location=256
>> [  849.719642] UDF-fs: error (device md0): udf_read_tagged: read 
>> failed, block=512, location=512
>> [  849.719643] UDF-fs: warning (device md0): udf_fill_super: No 
>> partition found (1)
>> [  849.719667] isofs_fill_super: bread failed, dev=md0, iso_blknum=16, 
>> block=32
>>
>> Thanks a lot for your helping
>> Rudy Zijlstra <mailto:rudy@grumpydevil.homelinux.org>
>> 11 de octubre de 2017, 12:42
>> Hi Joseba,
>>
>>
>>
>> Let me see if i understand you correctly
>>
>> - with all 4 disks plugged in, your system does not boot
>> - with the broken disk unplugged, it boots (and from your description 
>> it is really broken, no DISK recovery possible unless by specialised 
>> company)
>> - raid does not get assembled during boot, you do a manual assembly?
>>      -> please provide the command you are using
>>
>> from the log above, you should be able to do a mount of /dev/md0 which 
>> would auto-start the raid.
>>
>> If that works, the next step would be to check the health of the other 
>> disks. smartctl would be your friend.
>> Another useful action would be to copy all important data to a backup 
>> before you add a new disk to replace the failed disk.
>>
>> Cheers
>>
>> Rudy
>
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Re: Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Hi all. After latest advises from Neil i did fsck /dev/md0p1 and then 
asked me to fix some nodes and blocks. I said yes, then I mounted 
and....EUREKA!!!!!

Just to say thank you to all of you. I'm really happy.

Thanks, thanks, thanks!!

I know all of this is for helping to people, but, I would love gift you 
a beer, so, just give me by private email your paypal email and you will 
have your worthy beer.

Cheers!!!

Joseba Ibarra

Re: Can't mount /dev/md0 Raid5

[John Stoffel]

>>>>> "Mikael" == Mikael Abrahamsson <swmike@swm.pp.se> writes:

Mikael> On Wed, 11 Oct 2017, Joseba Ibarra wrote:
>> Now I see the RAID, however can't be mounted. So, I'm not sure how to backup 
>> the data. Gparted shows the partition /dev/md0p1 with the used and free 
>> space.

Mikael> Do you know what file system you had? Looks like next step is to try to 
Mikael> run fsck -n (read-only) on md0 and/or md0p1.

Mikael> What does /etc/fstab contain regarding md0?

Did you have the RAID5 setup as a PV inside a VG?  What does:

    vgscan

give you back when you run it as root?

Re: Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Hi John,

The 4 disk are into a HP Proliant where I run Proxmox. The RAID is 
linked to a particular Virtual Machine with Debian 9. It worked fine 
until I broke stopping a proccess giving permissions to a specific 
directory into the RAID. Then it crashed.

Doing vgscan

root@grafico:/mnt# vgscan
   Reading volume groups from cache.

I keep as root all the time while i try to recover RAID or at least data 
files.

I had to remove the fstab line for /dev/md0 since an error comes out.

If I add the line to /etc/fstab

UUID=xxxx-xxxx--xxxxxx /media/raid5  ext4 defaults 0 0

where UUID is the UUID for /dev/md0p1

the error I get booting is showed in picture

http://64bits.es/boot.png

Thanks for your time
> John Stoffel <mailto:john@stoffel.org>
> 11 de octubre de 2017, 21:49
>>>>>> "Mikael" == Mikael Abrahamsson<swmike@swm.pp.se>  writes:
>
> Mikael>  On Wed, 11 Oct 2017, Joseba Ibarra wrote:
>>> Now I see the RAID, however can't be mounted. So, I'm not sure how to backup
>>> the data. Gparted shows the partition /dev/md0p1 with the used and free
>>> space.
>
> Mikael>  Do you know what file system you had? Looks like next step is to try to
> Mikael>  run fsck -n (read-only) on md0 and/or md0p1.
>
> Mikael>  What does /etc/fstab contain regarding md0?
>
> Did you have the RAID5 setup as a PV inside a VG?  What does:
>
>      vgscan
>
> give you back when you run it as root?
>
> Mikael Abrahamsson <mailto:swmike@swm.pp.se>
> 11 de octubre de 2017, 16:01
> On Wed, 11 Oct 2017, Joseba Ibarra wrote:
>
>
> Do you know what file system you had? Looks like next step is to try 
> to run fsck -n (read-only) on md0 and/or md0p1.
>
> What does /etc/fstab contain regarding md0?
>
> Joseba Ibarra <mailto:wajalotnet@gmail.com>
> 11 de octubre de 2017, 13:56
> Hi Adam
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> md0 : inactive sdd1[3] sdb1[1] sdc1[2]
>       2929889280 blocks super 1.2
>
> unused devices: <none>
>
>
> root@grafico:/mnt# mdadm --manage /dev/md0 --stop
> mdadm: stopped /dev/md0
>
>
> root@grafico:/mnt# mdadm --assemble /dev/md0 /dev/sd[bcd]1
> mdadm: /dev/md0 assembled from 3 drives - not enough to start the 
> array while not clean - consider --force.
>
>
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> unused devices: <none>
>
> At this point I´ve followed the advise using --force
>
> root@grafico:/mnt# mdadm --assemble --force /dev/md0 /dev/sd[bcd]1
> mdadm: Marking array /dev/md0 as 'clean'
> mdadm: /dev/md0 has been started with 3 drives (out of 4).
>
>
> root@grafico:/mnt# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] 
> [raid4] [raid10]
> md0 : active (auto-read-only) raid5 sdb1[1] sdd1[3] sdc1[2]
>       2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
> [4/3] [_UUU]
>       bitmap: 0/8 pages [0KB], 65536KB chunk
>
> unused devices: <none>
>
>
> Now I see the RAID, however can't be mounted. So, I'm not sure how to 
> backup the data. Gparted shows the partition /dev/md0p1 with the used 
> and free space.
>
>
> If I try
>
> mount /dev/md0 /mnt
>
> again the output is
>
> mount: wrong file system, bad option, bad superblock in /dev/md0, 
> missing codepage or helper program, or other error
>
>     In some cases useful info is found in syslog - try dmesg | tail or 
> something like that.
>
> I do dmesg | tail
>
> If I try root@grafico:/mnt# mount /dev/md0p1 /mnt
> mount: /dev/md0p1: can't read superblock
>
> And
>
>
> root@grafico:/mnt# dmesg | tail
> [ 3263.411724] VFS: Dirty inode writeback failed for block device 
> md0p1 (err=-5).
> [ 3280.486813]  md0: p1
> [ 3280.514024]  md0: p1
> [ 3452.496811] UDF-fs: warning (device md0): udf_fill_super: No 
> partition found (2)
> [ 3463.731052] JBD2: Invalid checksum recovering block 630194476 in log
> [ 3464.933960] Buffer I/O error on dev md0p1, logical block 630194474, 
> lost async page write
> [ 3464.933971] Buffer I/O error on dev md0p1, logical block 630194475, 
> lost async page write
> [ 3465.928066] JBD2: recovery failed
> [ 3465.928070] EXT4-fs (md0p1): error loading journal
> [ 3465.936852] VFS: Dirty inode writeback failed for block device 
> md0p1 (err=-5).
>
>
> Thanks a lot for your time
>
>
> Joseba Ibarra
>
> Adam Goryachev <mailto:adam@websitemanagers.com.au>
> 11 de octubre de 2017, 13:29
> Hi Rudy,
>
> Please send the output of all of the following commands:
>
> cat /proc/mdstat
>
> mdadm --manage /dev/md0 --stop
>
> mdadm --assemble /dev/md0 /dev/sd[bcd]1
>
> cat /proc/mdstat
>
> mdadm --manage /dev/md0 --run
>
> mdadm --manage /dev/md0 --readwrite
>
> cat /proc/mdstat
>
>
> Basically the above is just looking at what the system has done 
> currently, stopping/clearing that, and then trying to assemble it 
> again, finally, we try to start it, even if it has one faulty disk.
>
> At this stage, chances look good for recovering all your data, though 
> I would advise to get yourself a replacement disk for the dead one so 
> that you can restore redundancy as soon as possible.
>
> Regards,Adam
>
>
>
>
>
> Joseba Ibarra <mailto:wajalotnet@gmail.com>
> 11 de octubre de 2017, 13:14
> Hi Rudy
>
> 1- Yes, with all 4 disk plugged in, system does not boot
> 2- Yes, with the broken disk unplugged, it boots
> 3 - Yes, raid does not assemble during boot. I assemble manually doing
>
> root@grafico:/home/jose# mdadm --assemble --scan /dev/md0
> root@grafico:/home/jose# mdadm --assemble --scan
> root@grafico:/home/jose# mdadm --assemble /dev/md0
>
> 4 -When I try to mount
>
>   mount /dev/md0 /mnt
>
> mount: wrong file system, bad option, bad superblock in /dev/md0, 
> missing codepage or helper program, or other error
>
>     In some cases useful info is found in syslog - try dmesg | tail or 
> something like that.
>
> I do dmesg | tail
>
> root@grafico:/mnt# dmesg | tail
> [  705.021959] md: pers->run() failed ...
> [  849.719439] EXT4-fs (md0): unable to read superblock
> [  849.719564] EXT4-fs (md0): unable to read superblock
> [  849.719589] EXT4-fs (md0): unable to read superblock
> [  849.719616] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=256, location=256
> [  849.719625] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=512, location=512
> [  849.719638] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=256, location=256
> [  849.719642] UDF-fs: error (device md0): udf_read_tagged: read 
> failed, block=512, location=512
> [  849.719643] UDF-fs: warning (device md0): udf_fill_super: No 
> partition found (1)
> [  849.719667] isofs_fill_super: bread failed, dev=md0, iso_blknum=16, 
> block=32
>
> Thanks a lot for your helping

Can't mount /dev/md0 Raid5

[Joseba Ibarra]

Hi.I have a RAID5 using 4 drives in a HO Proliant G8 Microserver

I got a Proxmox installed and the disks for RAID are associated with a 
specific VM with Debian 9. It worked like a charm.

But, some days ago i broke a proccess giving some permissions (sudo 
chmod....) to some folders into of the mounted /dev/md0. Then after 
restart the VM the RAID din't mount again. The raid contents very 
important data for me, so i'm not very sure what to do in order don't 
lose the data. So, i´m getting bit panic.

I need some guide to rebuild the system without losing the content.

mdadm version is 3.4-4+b1


This is the result of the fdisk -l related with the RAID

root@grafico:/# fdisk -l
Disco /dev/sdb: 931,5 GiB, 1000204886016 bytes, 1953525168 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 512 bytes / 512 bytes
Tipo de etiqueta de disco: dos
Identificador del disco: 0x087383f0

Disposit.  Inicio Comienzo      Final   Sectores Tamaño Id Tipo
/dev/sdb1             2048 1953523711 1953521664 931,5G fd Linux raid 
autodetect


Disco /dev/sdd: 931,5 GiB, 1000204886016 bytes, 1953525168 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 512 bytes / 512 bytes
Tipo de etiqueta de disco: dos
Identificador del disco: 0x8b48be4a

Disposit.  Inicio Comienzo      Final   Sectores Tamaño Id Tipo
/dev/sdd1             2048 1953523711 1953521664 931,5G fd Linux raid 
autodetect


Disco /dev/sdc: 931,5 GiB, 1000204886016 bytes, 1953525168 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 512 bytes / 512 bytes
Tipo de etiqueta de disco: dos
Identificador del disco: 0x87ea0d19

Disposit.  Inicio Comienzo      Final   Sectores Tamaño Id Tipo
/dev/sdc1             2048 1953523711 1953521664 931,5G fd Linux raid 
autodetect


Disco /dev/sde: 931,5 GiB, 1000204886016 bytes, 1953525168 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 512 bytes / 512 bytes
Tipo de etiqueta de disco: dos
Identificador del disco: 0xa69b0d7f

Disposit.  Inicio Comienzo      Final   Sectores Tamaño Id Tipo
/dev/sde1             2048 1953523711 1953521664 931,5G fd Linux raid 
autodetect


Disco /dev/md0: 2,7 TiB, 3000206622720 bytes, 5859778560 sectores
Unidades: sectores de 1 * 512 = 512 bytes
Tamaño de sector (lógico/físico): 512 bytes / 512 bytes
Tamaño de E/S (mínimo/óptimo): 524288 bytes / 1572864 bytes
Tipo de etiqueta de disco: gpt
Identificador del disco: A87C8BBF-5876-4FA6-83F6-46DAF1BDCF75

Disposit.  Comienzo      Final   Sectores Tamaño Tipo
/dev/md0p1     2048 5859776511 5859774464 2,7T Sistema de ficheros de Linux




And here some more information (as you can see the /dev/sde drive have 
some bad blocks)

root@grafico:/# mdadm --examine /dev/sdb
/dev/sdb:
    MBR Magic : aa55
Partition[0] :   1953521664 sectors at         2048 (type fd)
root@grafico:/# mdadm --examine /dev/sdc
/dev/sdc:
    MBR Magic : aa55
Partition[0] :   1953521664 sectors at         2048 (type fd)
root@grafico:/# mdadm --examine /dev/sdd
/dev/sdd:
    MBR Magic : aa55
Partition[0] :   1953521664 sectors at         2048 (type fd)
root@grafico:/# mdadm --examine /dev/sde
/dev/sde:
    MBR Magic : aa55
Partition[0] :   1953521664 sectors at         2048 (type fd)

root@grafico:/# mdadm --examine /dev/sdb1
/dev/sdb1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
Name : servidor:0
    Creation Time : Sat Aug 5 23:10:50 2017
    Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 1953259520 (931.39 GiB 1000.07 GB)
  Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
  Data Offset : 262144 sectors
  Super Offset : 8 sectors
  Unused Space : before=262056 sectors, after=0 sectors
  State : clean
  Device UUID : ddc94c8e:aab339df:2233112a:5c938bab

Internal Bitmap : 8 sectors from superblock
Update Time : Tue Sep 19 01:36:51 2017
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 626e25ae - correct
Events : 3106

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 0
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)

root@grafico:/# mdadm --examine /dev/sdc1
/dev/sdc1:
           Magic : a92b4efc
         Version : 1.2
     Feature Map : 0x1
      Array UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
            Name : servidor:0
   Creation Time : Sat Aug 5 23:10:50 2017
      Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 1953259520 (931.39 GiB 1000.07 GB)
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
     Data Offset : 262144 sectors
    Super Offset : 8 sectors
    Unused Space : before=262056 sectors, after=0 sectors
           State : clean
     Device UUID : 32271db0:38a5220c:c19968af:8fe1a3fb

Internal Bitmap : 8 sectors from superblock
     Update Time : Tue Sep 19 01:36:51 2017
   Bad Block Log : 512 entries available at offset 72 sectors
        Checksum : 86971d3c - correct
          Events : 3106

          Layout : left-symmetric
      Chunk Size : 512K

    Device Role : Active device 1
    Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
root@grafico:/# mdadm --examine /dev/sdd1
/dev/sdd1:
           Magic : a92b4efc
         Version : 1.2
     Feature Map : 0x1
      Array UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
            Name : servidor:0
   Creation Time : Sat Aug 5 23:10:50 2017
      Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 1953259520 (931.39 GiB 1000.07 GB)
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
     Data Offset : 262144 sectors
    Super Offset : 8 sectors
    Unused Space : before=262056 sectors, after=0 sectors
           State : clean
     Device UUID : 9014cf8b:ea7e22e2:9274be9d:9aeee689

Internal Bitmap : 8 sectors from superblock
     Update Time : Tue Sep 19 01:36:51 2017
   Bad Block Log : 512 entries available at offset 72 sectors
        Checksum : b4e1cc29 - correct
          Events : 3106

          Layout : left-symmetric
      Chunk Size : 512K

    Device Role : Active device 2
    Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
root@grafico:/# mdadm --examine /dev/sde1
/dev/sde1:
           Magic : a92b4efc
         Version : 1.2
     Feature Map : 0x9
      Array UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
            Name : servidor:0
   Creation Time : Sat Aug 5 23:10:50 2017
      Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 1953259520 (931.39 GiB 1000.07 GB)
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
     Data Offset : 262144 sectors
    Super Offset : 8 sectors
    Unused Space : before=262056 sectors, after=0 sectors
           State : clean
     Device UUID : f95affb4:138bca63:d10df091:1f20af37

Internal Bitmap : 8 sectors from superblock
     Update Time : Tue Sep 19 01:36:51 2017
   Bad Block Log : 512 entries available at offset 72 sectors - bad 
blocks present.
        Checksum : 1b3e988 - correct
          Events : 3106

          Layout : left-symmetric
      Chunk Size : 512K

    Device Role : Active device 3
    Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)




root@grafico:/# mdadm --detail /dev/md0
/dev/md0:
         Version : 1.2
   Creation Time : Sat Aug 5 23:10:50 2017
      Raid Level : raid5
      Array Size : 2929889280 (2794.16 GiB 3000.21 GB)
   Used Dev Size : 976629760 (931.39 GiB 1000.07 GB)
    Raid Devices : 4
   Total Devices : 4
     Persistence : Superblock is persistent

   Intent Bitmap : Internal

     Update Time : Tue Sep 19 01:36:51 2017
           State : clean
  Active Devices : 4
Working Devices : 4
  Failed Devices : 0
   Spare Devices : 0

          Layout : left-symmetric
      Chunk Size : 512K

            Name : servidor:0
            UUID : 0b44a3b8:83eafabc:644afc87:bdb5b1f3
          Events : 3106

     Number   Major   Minor   RaidDevice State
        0       8       17        0      active sync   /dev/sdb1
        1       8       33        1      active sync   /dev/sdc1
        2       8       49        2      active sync   /dev/sdd1
        3       8       65        3      active sync   /dev/sde1




root@grafico:/# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [linear] [multipath] [raid0] 
[raid1] [raid10]
md0 : active (auto-read-only) raid5 sdb1[0] sde1[3] sdc1[1] sdd1[2]
       2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
[4/4] [UUUU]
       bitmap: 0/8 pages [0KB], 65536KB chunk


Joseba Ibarra

Re: Can't mount /dev/md0 Raid5

[NeilBrown]

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On Fri, Sep 22 2017, Joseba Ibarra wrote:

> Hi.I have a RAID5 using 4 drives in a HO Proliant G8 Microserver
>
> I got a Proxmox installed and the disks for RAID are associated with a 
> specific VM with Debian 9. It worked like a charm.
>
> But, some days ago i broke a proccess giving some permissions (sudo 
> chmod....) to some folders into of the mounted /dev/md0. Then after 
> restart the VM the RAID din't mount again. The raid contents very 
> important data for me, so i'm not very sure what to do in order don't 
> lose the data. So, i´m getting bit panic.
>
> I need some guide to rebuild the system without losing the content.

Thanks for providing lots of useful data.

>
> root@grafico:/# cat /proc/mdstat
> Personalities : [raid6] [raid5] [raid4] [linear] [multipath] [raid0] 
> [raid1] [raid10]
> md0 : active (auto-read-only) raid5 sdb1[0] sde1[3] sdc1[1] sdd1[2]
>        2929889280 blocks super 1.2 level 5, 512k chunk, algorithm 2 
> [4/4] [UUUU]
>        bitmap: 0/8 pages [0KB], 65536KB chunk

It appears that md0 has been successfully assembled.  What does it
contain? What do you expect it to contain?  ext4? xfs? btrfs? LVM volume
??

What does "pvscan" show?
What does "fsck -n /dev/md0" show?
What happens when you "mount /dev/md0 /mnt" ?

NeilBrown

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