Software RAID 5 problem

Posted on 2005-03-17
Medium Priority
Last Modified: 2008-03-17
I've got a big problem with my raid 5 on my linux redhat machine. I'm testing my software raid 5 at the moment, so i thought by myself i pull out a disk and put it back in, but it turned out i pulled out the worng one. so after putting it back in i pulled out another disk.
Now when i boot my linux redhat i'll get an error like this:

an error accurred during RAID sartup
starting up raid devices : mdadm : /dev/md0 assemble from 3 drives

not enough to start the array
/dev/md0 : invalid argument
/dev/md0 : is nog a RAID0or liniear array

who helps me out here
I can login to  a RAID REPAIR shell but don't know what todo

when i use the raid tools i'll get the following errors

lsraid -a /dev/md0
output: lsraid -mddevice [9, 0] /dev/md0 is offline: please specify the dis query.

mdadm --detail /dev/md0
mdadm: md device /dev/md0 does nog appear to be online

thnx in advance
Question by:Mr-sark
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Accepted Solution

rhino_man earned 750 total points
ID: 13573616
Had a similar situation.. Let's start by determining which drives/partitions are part of the array.  We can't do a 'cat /proc/mdstat' because your array isn't active.

If you know one of the drives and partition, specify it here.  I use hd(x)4 for my arrays...  if you used hdb, then the following should help:

mdadm -D /dev/hdb4

You can check what partitions are on the drive with cfdisk/fdisk... or the following:

sfdisk -d /dev/hdb
Should give you something like this.  If the device was set up with the persistent superblock, you'll have a partition type of 'fd' or 0xfd :

/dev/hda1 : start=       63, size=   192717, Id=83
/dev/hda2 : start=   192780, size=   996030, Id=82
/dev/hda3 : start=  1188810, size= 23438835, Id=83
/dev/hda4 : start= 24627645, size= /dev/hda1 : start=       63, size=   192717, Id=83
/dev/hda2 : start=   192780, size=   996030, Id=82
/dev/hda3 : start=  1188810, size= 23438835, Id=83
/dev/hda95474295, Id=fd

Once you get this information, send it back to this thread, and we'll help you rebuild your array and get it going (if possible)

Good luck,


Expert Comment

ID: 13574358
Correcting myself here...  Once you find out a partition that should be part of your raid set :

mdadm --examine /dev/hda4  (drive and partition here)

You'll get output something like this:

          Magic : a92b4efc
        Version : 00.90.00
           UUID : 45008a00:6ebc837c:c02320fa:8a15251d
  Creation Time : Fri May  2 10:53:31 2003
     Raid Level : raid1
    Device Size : 47737024 (45.53 GiB 48.88 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 0

    Update Time : Thu Mar 17 20:20:01 2005
          State : dirty
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0
       Checksum : 2ae6c0a3 - correct
         Events : 0.245

      Number   Major   Minor   RaidDevice State
this     0       3        4        0      active sync   /dev/hda4

   0     0       3        4        0      active sync   /dev/hda4
   1     1       3       68        1      active sync   /dev/hdb4

Then you can assemble it via :

mdadm --assemble /dev/md1 /dev/hda4 /dev/hdb4


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