On Tue Dec 09, 2014 at 12:35:14AM -0500, Emery Guevremont wrote:
> >> >> >> On Mon, Dec 8, 2014 at 4:48 AM, Robin Hill <robin@xxxxxxxxxxxxxxx> wrote:
> >> >> >> > On Sat Dec 06, 2014 at 03:49:10PM -0500, Emery Guevremont wrote:
> >> >> >> >> > On Sat Dec 06, 2014 at 01:35:50pm -0500, Emery Guevremont wrote:
> >> >> >> >> >
> >> >> >> >> >> The long story and what I've done.
> >> >> >> >> >>
> >> >> >> >> >> /dev/md0 is assembled with 4 drives
> >> >> >> >> >> /dev/sda3
> >> >> >> >> >> /dev/sdb3
> >> >> >> >> >> /dev/sdc3
> >> >> >> >> >> /dev/sdd3
> >> >> >> >> >>
> >> >> >> >> >> 2 weeks ago, mdadm marked /dev/sda3 as failed. cat /proc/mdstat showed
> >> >> >> >> >> _UUU. smarctl also confirmed that the drive was dying. So I shutdown
> >> >> >> >> >> the server and until I received a replacement drive.
> >> >> >> >> >>
> >> >> >> >> >> This week, I replaced the dying drive with my new drive. Booted into
> >> >> >> >> >> single user mode and did this:
> >> >> >> >> >>
> >> >> >> >> >> mdadm --manage /dev/md0 --add /dev/sda3 a cat of /proc/mdstat
> >> >> >> >> >> confirmed the resyncing process. The last time I checked it was up to
> >> >> >> >> >> 11%. After a few minutes later, I noticed that the syncing stopped. A
> >> >> >> >> >> read error message on /dev/sdd3 (have a pic of it if interested)
> >> >> >> >> >> appear on the console. It appears that /dev/sdd3 might be going bad. A
> >> >> >> >> >> cat /proc/mdstat showed _U_U. Now I panic, and decide to leave
> >> >> >> >> >> everything as is and to go to bed.
> >> >> >> >> >>
> >> >> >> >> >> The next day, I shutdown the server and reboot with a live usb distro
> >> >> >> >> >> (Ubuntu rescue remix). After booting into the live distro, a cat
> >> >> >> >> >> /proc/mdstat showed that my /dev/md0 was detected but all drives had
> >> >> >> >> >> an (S) next to it. i.e. /dev/sda3 (S)... Naturally I don't like the
> >> >> >> >> >> looks of this.
> >> >> >> >> >>
> >> >> >> >> >> I ran ddrescue to copy /dev/sdd onto my new replacement disk
> >> >> >> >> >> (/dev/sda). Everything, worked, ddrescue got only one read error, but
> >> >> >> >> >> was eventually able to read the bad sector on a retry. I followed up
> >> >> >> >> >> by also cloning with ddrescue, sdb and sdc.
> >> >> >> >> >>
> >> >> >> >> >> So now I have cloned copies of sdb, sdc and sdd to work with.
> >> >> >> >> >> Currently running mdadm --assemble --scan, will activate my array, but
> >> >> >> >> >> all drives are added as spares. Running mdadm --examine on each
> >> >> >> >> >> drives, shows the same Array UUID number, but the Raid Devices is 0
> >> >> >> >> >> and raid level is -unknown- for some reason. The rest seems fine and
> >> >> >> >> >> makes sense. I believe I could re-assemble my array if I could define
> >> >> >> >> >> the raid level and raid devices.
> >> >> >> >> >>
> >> >> >> >> >> I wanted to know if there are a way to restore my superblocks from the
> >> >> >> >> >> examine command I ran at the beginning? If not, what mdadm create
> >> >> >> >> >> command should I run? Also please let me know if drive ordering is
> >> >> >> >> >> important, and how I can determine this with the examine output I'll
> >> >> >> >> >> got?
> >> >> >> >> >>
> >> >> >> >> >> Thank you.
> >> >> >> >> >>
> >> >> >> >> You'll see from the examine output, raid level and devices aren't
> >> >> >> >> defined and notice the role of each drives. The examine output (I
> >> >> >> >> attached 4 files) that I took right after the read error during the
> >> >> >> >> synching process seems to show a more accurate superblock. Here's also
> >> >> >> >> the output of mdadm --detail /dev/md0 that I took when I got the first
> >> >> >> >> error:
> >> >> >> >>
> >> >> >> >> ARRAY /dev/md/0 metadata=1.2 UUID=cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> name=runts:0
> >> >> >> >> spares=1
> >> >> >> >>
> >> >> >> >>
> >> >> >> >> Here's the output of how things currently are:
> >> >> >> >>
> >> >> >> >> mdadm --assemble --force /dev/md127 /dev/sdb3 /dev/sdc3 /dev/sdd3
> >> >> >> >> mdadm: /dev/md127 assembled from 0 drives and 3 spares - not enough to
> >> >> >> >> start the array.
> >> >> >> >>
> >> >> >> >> dmesg
> >> >> >> >> [27903.423895] md: md127 stopped.
> >> >> >> >> [27903.434327] md: bind<sdc3>
> >> >> >> >> [27903.434767] md: bind<sdd3>
> >> >> >> >> [27903.434963] md: bind<sdb3>
> >> >> >> >>
> >> >> >> >> cat /proc/mdstat
> >> >> >> >> root@ubuntu:~# cat /proc/mdstat
> >> >> >> >> Personalities : [raid6] [raid5] [raid4] [linear] [multipath] [raid0]
> >> >> >> >> [raid1] [raid10]
> >> >> >> >> md127 : inactive sdb3[4](S) sdd3[0](S) sdc3[5](S)
> >> >> >> >> 5858387208 blocks super 1.2
> >> >> >> >>
> >> >> >> >> mdadm --examine /dev/sd[bcd]3
> >> >> >> >> /dev/sdb3:
> >> >> >> >> Magic : a92b4efc
> >> >> >> >> Version : 1.2
> >> >> >> >> Feature Map : 0x0
> >> >> >> >> Array UUID : cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> Name : runts:0
> >> >> >> >> Creation Time : Tue Jul 26 03:27:39 2011
> >> >> >> >> Raid Level : -unknown-
> >> >> >> >> Raid Devices : 0
> >> >> >> >>
> >> >> >> >> Avail Dev Size : 3905591472 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Data Offset : 2048 sectors
> >> >> >> >> Super Offset : 8 sectors
> >> >> >> >> State : active
> >> >> >> >> Device UUID : b2bf0462:e0722254:0e233a72:aa5df4da
> >> >> >> >>
> >> >> >> >> Update Time : Sat Dec 6 12:46:40 2014
> >> >> >> >> Checksum : 5e8cfc9a - correct
> >> >> >> >> Events : 1
> >> >> >> >>
> >> >> >> >>
> >> >> >> >> Device Role : spare
> >> >> >> >> Array State : ('A' == active, '.' == missing)
> >> >> >> >> /dev/sdc3:
> >> >> >> >> Magic : a92b4efc
> >> >> >> >> Version : 1.2
> >> >> >> >> Feature Map : 0x0
> >> >> >> >> Array UUID : cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> Name : runts:0
> >> >> >> >> Creation Time : Tue Jul 26 03:27:39 2011
> >> >> >> >> Raid Level : -unknown-
> >> >> >> >> Raid Devices : 0
> >> >> >> >>
> >> >> >> >> Avail Dev Size : 3905591472 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Data Offset : 2048 sectors
> >> >> >> >> Super Offset : 8 sectors
> >> >> >> >> State : active
> >> >> >> >> Device UUID : 390bd4a2:07a28c01:528ed41e:a9d0fcf0
> >> >> >> >>
> >> >> >> >> Update Time : Sat Dec 6 12:46:40 2014
> >> >> >> >> Checksum : f69518c - correct
> >> >> >> >> Events : 1
> >> >> >> >>
> >> >> >> >>
> >> >> >> >> Device Role : spare
> >> >> >> >> Array State : ('A' == active, '.' == missing)
> >> >> >> >> /dev/sdd3:
> >> >> >> >> Magic : a92b4efc
> >> >> >> >> Version : 1.2
> >> >> >> >> Feature Map : 0x0
> >> >> >> >> Array UUID : cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> Name : runts:0
> >> >> >> >> Creation Time : Tue Jul 26 03:27:39 2011
> >> >> >> >> Raid Level : -unknown-
> >> >> >> >> Raid Devices : 0
> >> >> >> >>
> >> >> >> >> Avail Dev Size : 3905591472 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Data Offset : 2048 sectors
> >> >> >> >> Super Offset : 8 sectors
> >> >> >> >> State : active
> >> >> >> >> Device UUID : 92589cc2:9d5ed86c:1467efc2:2e6b7f09
> >> >> >> >>
> >> >> >> >> Update Time : Sat Dec 6 12:46:40 2014
> >> >> >> >> Checksum : 571ad2bd - correct
> >> >> >> >> Events : 1
> >> >> >> >>
> >> >> >> >>
> >> >> >> >> Device Role : spare
> >> >> >> >> Array State : ('A' == active, '.' == missing)
> >> >> >> >>
> >> >> >> >> and finally kernel and mdadm versions:
> >> >> >> >>
> >> >> >> >> uname -a
> >> >> >> >> Linux ubuntu 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:41:14 UTC
> >> >> >> >> 2012 i686 i686 i386 GNU/Linux
> >> >> >> >>
> >> >> >> >> mdadm -V
> >> >> >> >> mdadm - v3.2.3 - 23rd December 2011
> >> >> >> >
> >> >> >> >> /dev/sda3:
> >> >> >> >> Magic : a92b4efc
> >> >> >> >> Version : 1.2
> >> >> >> >> Feature Map : 0x0
> >> >> >> >> Array UUID : cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> Name : runts:0 (local to host runts)
> >> >> >> >> Creation Time : Mon Jul 25 23:27:39 2011
> >> >> >> >> Raid Level : raid5
> >> >> >> >> Raid Devices : 4
> >> >> >> >>
> >> >> >> >> Avail Dev Size : 3905591472 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Array Size : 5858385408 (5586.99 GiB 5998.99 GB)
> >> >> >> >> Used Dev Size : 3905590272 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Data Offset : 2048 sectors
> >> >> >> >> Super Offset : 8 sectors
> >> >> >> >> State : clean
> >> >> >> >> Device UUID : b2bf0462:e0722254:0e233a72:aa5df4da
> >> >> >> >>
> >> >> >> >> Update Time : Tue Dec 2 23:15:37 2014
> >> >> >> >> Checksum : 5ed5b898 - correct
> >> >> >> >> Events : 3925676
> >> >> >> >>
> >> >> >> >> Layout : left-symmetric
> >> >> >> >> Chunk Size : 512K
> >> >> >> >>
> >> >> >> >> Device Role : spare
> >> >> >> >> Array State : A.A. ('A' == active, '.' == missing)
> >> >> >> >
> >> >> >> >> /dev/sdb3:
> >> >> >> >> Magic : a92b4efc
> >> >> >> >> Version : 1.2
> >> >> >> >> Feature Map : 0x0
> >> >> >> >> Array UUID : cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> Name : runts:0 (local to host runts)
> >> >> >> >> Creation Time : Mon Jul 25 23:27:39 2011
> >> >> >> >> Raid Level : raid5
> >> >> >> >> Raid Devices : 4
> >> >> >> >>
> >> >> >> >> Avail Dev Size : 3905591472 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Array Size : 5858385408 (5586.99 GiB 5998.99 GB)
> >> >> >> >> Used Dev Size : 3905590272 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Data Offset : 2048 sectors
> >> >> >> >> Super Offset : 8 sectors
> >> >> >> >> State : clean
> >> >> >> >> Device UUID : 92589cc2:9d5ed86c:1467efc2:2e6b7f09
> >> >> >> >>
> >> >> >> >> Update Time : Tue Dec 2 23:15:37 2014
> >> >> >> >> Checksum : 57638ebb - correct
> >> >> >> >> Events : 3925676
> >> >> >> >>
> >> >> >> >> Layout : left-symmetric
> >> >> >> >> Chunk Size : 512K
> >> >> >> >>
> >> >> >> >> Device Role : Active device 0
> >> >> >> >> Array State : A.A. ('A' == active, '.' == missing)
> >> >> >> >
> >> >> >> >> /dev/sdc3:
> >> >> >> >> Magic : a92b4efc
> >> >> >> >> Version : 1.2
> >> >> >> >> Feature Map : 0x0
> >> >> >> >> Array UUID : cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> Name : runts:0 (local to host runts)
> >> >> >> >> Creation Time : Mon Jul 25 23:27:39 2011
> >> >> >> >> Raid Level : raid5
> >> >> >> >> Raid Devices : 4
> >> >> >> >>
> >> >> >> >> Avail Dev Size : 3905591472 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Array Size : 5858385408 (5586.99 GiB 5998.99 GB)
> >> >> >> >> Used Dev Size : 3905590272 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Data Offset : 2048 sectors
> >> >> >> >> Super Offset : 8 sectors
> >> >> >> >> State : clean
> >> >> >> >> Device UUID : 390bd4a2:07a28c01:528ed41e:a9d0fcf0
> >> >> >> >>
> >> >> >> >> Update Time : Tue Dec 2 23:15:37 2014
> >> >> >> >> Checksum : fb20d8a - correct
> >> >> >> >> Events : 3925676
> >> >> >> >>
> >> >> >> >> Layout : left-symmetric
> >> >> >> >> Chunk Size : 512K
> >> >> >> >>
> >> >> >> >> Device Role : Active device 2
> >> >> >> >> Array State : A.A. ('A' == active, '.' == missing)
> >> >> >> >
> >> >> >> >> /dev/sdd3:
> >> >> >> >> Magic : a92b4efc
> >> >> >> >> Version : 1.2
> >> >> >> >> Feature Map : 0x0
> >> >> >> >> Array UUID : cf9db8fa:0c2bb553:46865912:704cceae
> >> >> >> >> Name : runts:0 (local to host runts)
> >> >> >> >> Creation Time : Mon Jul 25 23:27:39 2011
> >> >> >> >> Raid Level : raid5
> >> >> >> >> Raid Devices : 4
> >> >> >> >>
> >> >> >> >> Avail Dev Size : 3905591472 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Array Size : 5858385408 (5586.99 GiB 5998.99 GB)
> >> >> >> >> Used Dev Size : 3905590272 (1862.33 GiB 1999.66 GB)
> >> >> >> >> Data Offset : 2048 sectors
> >> >> >> >> Super Offset : 8 sectors
> >> >> >> >> State : clean
> >> >> >> >> Device UUID : 4156ab46:bd42c10d:8565d5af:74856641
> >> >> >> >>
> >> >> >> >> Update Time : Tue Dec 2 23:14:03 2014
> >> >> >> >> Checksum : a126853f - correct
> >> >> >> >> Events : 3925672
> >> >> >> >>
> >> >> >> >> Layout : left-symmetric
> >> >> >> >> Chunk Size : 512K
> >> >> >> >>
> >> >> >> >> Device Role : Active device 1
> >> >> >> >> Array State : AAAA ('A' == active, '.' == missing)
> >> >> >> >
> >> >> >> > At least you have the previous data anyway, which should allow
> >> >> >> > reconstruction of the array. The device names have changed between your
> >> >> >> > two reports though, so I'd advise double-checking which is which before
> >> >> >> > proceeding.
> >> >> >> >
> >> >> >> > The reports indicate that the original array order (based on the device
> >> >> >> > role field) for the four devices was (using device UUIDs as they're
> >> >> >> > consistent):
> >> >> >> > 92589cc2:9d5ed86c:1467efc2:2e6b7f09
> >> >> >> > 4156ab46:bd42c10d:8565d5af:74856641
> >> >> >> > 390bd4a2:07a28c01:528ed41e:a9d0fcf0
> >> >> >> > b2bf0462:e0722254:0e233a72:aa5df4da
> >> >> >> >
> >> >> >> > That would give a current device order of sdd3,sda3,sdc3,sdb3 (I don't
> >> >> >> > have the current data for sda3, but that's the only missing UUID).
> >> >> >> >
> I had forgotten that I took a pic of the read error message, which
> also contained an output of /proc/mdstat, so I was able to determine
> the ordering and I ran this command:
>
What did that indicate, and how did you map it to the device order below?
> root@ubuntu:~# mdadm -v --create --assume-clean --level=5 --chunk=512
> --size=1952795136 --raid-devices=4 /dev/md0 /dev/sdd3 /dev/sdb3
> missing /dev/sdc3
> mdadm: layout defaults to left-symmetric
> mdadm: layout defaults to left-symmetric
> mdadm: /dev/sdd3 appears to be part of a raid array:
> level=raid5 devices=4 ctime=Tue Dec 9 05:17:53 2014
> mdadm: layout defaults to left-symmetric
> mdadm: /dev/sdb3 appears to be part of a raid array:
> level=raid5 devices=4 ctime=Tue Dec 9 05:17:53 2014
> mdadm: layout defaults to left-symmetric
> mdadm: /dev/sdc3 appears to be part of a raid array:
> level=raid5 devices=4 ctime=Tue Dec 9 05:17:53 2014
> Continue creating array? y
> mdadm: Defaulting to version 1.2 metadata
> mdadm: array /dev/md0 started.
>
> I did mdadm -E and everything seemed to be consistent with the
> original output of the examine command. So I ran fsck -n
>
> root@ubuntu:~# fsck -n /dev/md0
> fsck from util-linux 2.20.1
> e2fsck 1.42 (29-Nov-2011)
> fsck.ext4: Group descriptors look bad... trying backup blocks...
> Error writing block 1 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
>
> Error writing block 2 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
>
> Error writing block 3 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
>
> Error writing block 4 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
>
> Error writing block 5 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
>
> Error writing block 6 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
> ...
> ...
> Error writing block 343 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
>
> Error writing block 344 (Attempt to write block to filesystem resulted
> in short write). Ignore error? no
>
> fsck.ext4: Device or resource busy while trying to open /dev/md0
> Filesystem mounted or opened exclusively by another program?
>
>
> I believe I made some progress. But before I continue, I wanted to
> know if I was on the right track?
>
> I tried to mount /dev/md0 but got this:
>
> root@ubuntu:~# mount -t ext4 /dev/md0 /mnt/
> mount: wrong fs type, bad option, bad superblock on /dev/md0,
> missing codepage or helper program, or other error
> In some cases useful info is found in syslog - try
> dmesg | tail or so
>
> Am I at a point to run fsck to repair the ext4 superblock?
>
No, that output would definitely suggest you have the wrong order.
That looks to be far too many errors for a normal unclean shutdown
situation.
> I also tried a different ordering to see what fsck -n would give and I got:
>
> root@ubuntu:~# fsck -n /dev/md0
> fsck from util-linux 2.20.1
> e2fsck 1.42 (29-Nov-2011)
> fsck.ext4: Filesystem revision too high while trying to open /dev/md0
> The filesystem revision is apparently too high for this version of e2fsck.
> (Or the filesystem superblock is corrupt)
>
>
> The superblock could not be read or does not describe a correct ext2
> filesystem. If the device is valid and it really contains an ext2
> 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>
>
> Which seems to confirm my first attempt at the ordering was good.
>
No, it confirms that the first device was correct - the filesystem
superblock will be entirely within the first chunk, so only the first
disk needs to be correct for that to be readable.
Have you tried running it in the order I advised (sdd3, sda3, sdc3,
missing) or in the order of the UUIDs (if the device order has changed)?
92589cc2:9d5ed86c:1467efc2:2e6b7f09
4156ab46:bd42c10d:8565d5af:74856641
390bd4a2:07a28c01:528ed41e:a9d0fcf0
b2bf0462:e0722254:0e233a72:aa5df4da
If not, please do so first and see whether the fsck output is any
better.
Cheers,
Robin
--
___
( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
/ / ) | Little Jim says .... |
// !! | "He fallen in de water !!" |
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