> Thanks, it was an array that was up and running for a long time, and all
> of a sudden, this happened. so there were formatted and up and running
> fine.
Well, you didn't quite answer my question. Are the drives
partitioned, or not?
> If I run, `mdadm --examine /dev/sda` etc. on all my disks, I get the
> following error on all disks:
> mdadm: No md superblock detected on /dev/sda.
> thats on all disks... (sda, sdb, sdc, and sdd)
Well, we know the array is at least partially assembling, so it is
finding at least some of the superblocks. It sounds to me like perhaps the
drives are partitioned.
> When I run fdisk on /dev/sda I get the following error:
> Unable to read /dev/sda
That sounds like a dead drive. I suggest running SMART tests on it.
You might try changing the cable or moving it to another controller port.
> However, running fdisk on all other disks shows that they are up and
> formatted with "raid" file type.
Formatted, or partitioned? You might post the output from fdisk
when you type "p" at the FDISK prompt. At a guess, I would say perhaps your
drives are partitioned and the devices are /dev/sda1 (or 2, or 3, or 4,
...), /dev/sdb1, etc. Try typing
`ls /dev/sd*`
and see what pops up. There should be references to sda, sdb, etc. If
there are also references to sdb1, sdb2, etc, then your drives have valid
partitions, and it is those (or some of them, at least) which are targets
for md. Once you have determined which drives have which partitions, then
issue the commands
` mdadm --examine /dev/sdxy`, where x is "a", "b", "c", "d", etc., and y is
"1", "2", "3", etc., including only those values returned by the ls command.
For example, on one of my systems:
RAID-Server:/etc/ssmtp# ls /dev/sd*
/dev/sda /dev/sda2 /dev/sdb /dev/sdd /dev/sdf /dev/sdh /dev/sdj
/dev/sdl
/dev/sda1 /dev/sda3 /dev/sdc /dev/sde /dev/sdg /dev/sdi /dev/sdk
RAID-Server:/etc/ssmtp# ls /dev/hd*
/dev/hda /dev/hda1 /dev/hda2 /dev/hda3
This result tells us I have one PATA drive (hda) with three
partitions on it. It also tells us I have one (probably) SATA or SCSI drive
(sda) with three partitions, and 11 SATA or SCSI drives (sdb - sdl) with no
partitions on them.
If I issue the examine command on /dev/sda, I get an error:
RAID-Server:/etc/ssmtp# mdadm --examine /dev/sda
mdadm: No md superblock detected on /dev/sda.
That's because in this case the DRIVE does not have an md
superblock. It is the PARTITIONS which have superblocks:
RAID-Server:/etc/ssmtp# mdadm --examine /dev/sda1
/dev/sda1:
Magic : a92b4efc
Version : 1.0
Feature Map : 0x1
Array UUID : 76e8e11d:e0183c3c:404cb86a:19a7cb3d
Name : 'RAID-Server':1
Creation Time : Wed Dec 23 23:46:28 2009
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 803160 (392.23 MiB 411.22 MB)
Array Size : 803160 (392.23 MiB 411.22 MB)
Super Offset : 803168 sectors
State : clean
Device UUID : 28212297:1d982d5d:ce41b6fe:03720159
Internal Bitmap : 2 sectors from superblock
Update Time : Sat Dec 26 13:00:32 2009
Checksum : af8f04b1 - correct
Events : 204
Array Slot : 1 (failed, 1, 0)
Array State : uU 1 failed
The other 11 drives, however, are un-partitioned, and the md
superblock rests on the drive device itself:
RAID-Server:/etc/ssmtp# mdadm --examine /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 5ff10d73:a096195f:7a646bba:a68986ca
Name : 'RAID-Server':0
Creation Time : Sat Apr 25 01:17:12 2009
Raid Level : raid6
Raid Devices : 11
Avail Dev Size : 1953524896 (931.51 GiB 1000.20 GB)
Array Size : 17581722624 (8383.62 GiB 9001.84 GB)
Used Dev Size : 1953524736 (931.51 GiB 1000.20 GB)
Data Offset : 272 sectors
Super Offset : 8 sectors
State : clean
Device UUID : d40c9255:cef0739f:966d448d:e549ada8
Internal Bitmap : 2 sectors from superblock
Update Time : Sat Dec 26 15:09:44 2009
Checksum : e290ec2f - correct
Events : 1193460
Chunk Size : 256K
Array Slot : 0 (0, 1, 2, 3, 4, 5, 6, 10, 8, 9, 7)
Array State : Uuuuuuuuuuu
>
> Not sure what I can do next...
>
> Thanks
> Rick
>
>
>
>
>
>
> On Sat, 2009-12-26 at 12:47 -0600, Leslie Rhorer wrote:
> > I take it from your post the drives are not partitioned, and the
> > RAID array consists of raw disk members? First, check the superblocks
> of
> > the md devices:
> >
> > `mdadm --examine /dev/sda`, etc. If 2 or more of the superblocks
> > are corrupt, then that's your problem. If not, then it should be
> possible
> > to get the array mounted one way or the other. Once you get the array
> > assembled again, then you can repair it, if need be. Once that is done,
> you
> > can repair the file system if it is corrupted. Once everything is
> clean,
> > you can mount the file system, and if necessary attempt to recover any
> lost
> > files.
> >
> > > -----Original Message-----
> > > From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-
> > > owner@xxxxxxxxxxxxxxx] On Behalf Of Rick Bragg
> > > Sent: Friday, December 25, 2009 9:13 PM
> > > To: Linux RAID
> > > Subject: Re: fsck problems. Can't restore raid
> > >
> > > On Fri, 2009-12-25 at 21:47 -0500, Rick Bragg wrote:
> > > > On Fri, 2009-12-25 at 20:33 -0500, Rick Bragg wrote:
> > > > > Hi,
> > > > >
> > > > > I have a raid 10 array and for some reason the system went down
> and I
> > > > > can't get it back.
> > > > >
> > > > > during re-boot, I get the following error:
> > > > >
> > > > > 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>
> > > > >
> > > > > I have tried everything I can think of and I can't seem to do an
> fsck
> > > or
> > > > > repair the file system.
> > > > >
> > > > > what can I do?
> > > > >
> > > > > Thanks
> > > > > Rick
> > > > >
> > > >
> > > >
> > > > More info:
> > > >
> > > > My array is made up of /dev/sda, sdb, sdc, and sdd. However they
> are
> > > > not mounted right now. My OS is booted off of /dev/sde. I am
> running
> > > > ubuntu 9.04
> > > >
> > > > mdadm -Q --detail /dev/md0
> > > > mdadm: md device /dev/md0 does not appear to be active.
> > > >
> > > > Where do I take if from here? I'm not up on this as much as I
> should be
> > > > at all. In fact I am quite a newbe to this... Any help would be
> greatly
> > > > appreciated.
> > > >
> > > > Thanks
> > > > Rick
> > > >
> > >
> > >
> > > Here is even more info:
> > >
> > > # mdadm --assemble --scan
> > > mdadm: /dev/md0 assembled from 2 drives - not enough to start the
> array.
> > >
> > > # mdadm --assemble /dev/sda /dev/sdb /dev/sdc /dev/sdd
> > > mdadm: cannot open device /dev/sdb: Device or resource busy
> > > mdadm: /dev/sdb has no superblock - assembly aborted
> > >
> > > Is my array toast?
> > > What can I do?
> > >
> > > Thanks
> > > Rick
> > >
> > >
> >
> >
> > --
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> >
>
>
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