RAID1 Drive Removed?

Carlwill · 2009-10-29 13:55:31

I noticed today on my Arch Linux system that /dev/sda3 is missing from the mirror. I don't understand why or how to resolve this. Can someone please assist me in repairing the broken mirror?

[root@mail ~]# cat /proc/mdstat
Personalities : [raid1] 
md2 : active raid1 sdb3[1]
      728571776 blocks [2/1] [_U]
      
md1 : active raid1 sda2[0] sdb2[1]
      2000000 blocks [2/2] [UU]
      
md0 : active raid1 sda1[0] sdb1[1]
      1999936 blocks [2/2] [UU]

Then I checked to see if the following had any info...

[root@mail ~]# mdadm --misc --detail /dev/md2
/dev/md2:
        Version : 0.90
  Creation Time : Thu Oct 29 04:48:38 2009
     Raid Level : raid1
     Array Size : 728571776 (694.82 GiB 746.06 GB)
  Used Dev Size : 728571776 (694.82 GiB 746.06 GB)
   Raid Devices : 2
  Total Devices : 1
Preferred Minor : 2
    Persistence : Superblock is persistent

    Update Time : Thu Oct 29 09:52:12 2009
          State : clean, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 0
  Spare Devices : 0

           UUID : f46bd6c9:01829ddb:1da0a365:a6c675d9
         Events : 0.13

    Number   Major   Minor   RaidDevice State
       0       0        0        0      removed
       1       8       19        1      active sync   /dev/sdb3

iBertus · 2009-10-29 14:41:04

Has the drive failed? If so, you should replace the drive and resync before something happens to the other one and your data is lost.

Carlwill · 2009-10-29 14:45:21

No because I only have two physical drives in the machine.

/dev/sda1 & /dev/sdb1 = md0 (boot)
/dev/sda2 & /dev/sdb2 = md1 (swap)
/dev/sda3 & /dev/sdb3 = md2 (root)

If the drive failed, all the md devices would not be [UU] as shown above and also the section where it says, "Failed Devices; 0" would also be different. I don't understand enough about mdadm to resolve this but I am sure both drives are good and the system still works and boots fine!

iBertus · 2009-10-29 14:57:45

Try 'mdadm /dev/md2 --re-add /dev/sda3' without quotes.

Carlwill · 2009-10-29 15:01:15

[root@mail ~]# mdadm /dev/md2 --re-add /dev/sda3
mdadm: Cannot open /dev/sda3: Device or resource busy

ckristi · 2009-10-29 15:21:37

Carlwill wrote:

[root@mail ~]# mdadm /dev/md2 --re-add /dev/sda3
mdadm: Cannot open /dev/sda3: Device or resource busy

Is /dev/sda3 already mounted? What does df says? Also, check /etc/mtab to see if sda3 isn't already mounted somehow.

mawhii · 2009-10-30 00:51:50

I've got the same issue actually. df says not mounted, mtab says not mounted, but I CAN mount and unmount the drive manually.

I checked the grub menu.lst and it's for some reason showing to boot to that drive (/dev/sda3 for me, too.), so I'm assume it's some issue with booting there and trying to mount it later on somehow..

Servers' 3 hours away, so i'm not about to go and reboot it though. =P

Here's the part of my menu.lst that concerns me:

(0) Arch Linux
title Arch Linux [/boot/vmlinuz26]
root (hd0,0)
kernel /vmlinuz26 root=/dev/sda3 ro
initrd /kernel26.img

I could've sworn I set the rot to /dev/md0, but who knows. It's been a while since that was setup..

Can you check your menu.lst and see if that matches?

Carlwill · 2009-10-30 14:15:57

Funny I have the same thing. I even re-installed the entire system from scratch today and had the same problem upon boot up so the issue is either with Arch or the WIki instructions are not correct for whatever reason.

Here is my menu.lst

# (0) Arch Linux
title  Arch Linux
root   (hd0,0)
kernel /vmlinuz26 root=/dev/sda3 ro
initrd /kernel26.img

I am going to change the kernel line to read "kernel /vmlinuz26 root=/dev/md2 ro"

Chances are I will break the whole system but it's just a test box so I don't care.

Below is my "fstab" file:

/dev/md0 /boot ext4 defaults 0 1
/dev/md1 swap swap defaults 0 0
/dev/md2 / ext4 defaults 0 1

Below is the output of my fdisk -l:

Disk /dev/sdb: 750.2 GB, 750156374016 bytes
255 heads, 63 sectors/track, 91201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000b162b

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1         249     2000061   fd  Linux raid autodetect
/dev/sdb2             250         498     2000092+  fd  Linux raid autodetect
/dev/sdb3             499       91201   728571847+  fd  Linux raid autodetect

Disk /dev/sda: 750.2 GB, 750156374016 bytes
255 heads, 63 sectors/track, 91201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000b162b

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         249     2000061   fd  Linux raid autodetect
/dev/sda2             250         498     2000092+  fd  Linux raid autodetect
/dev/sda3             499       91201   728571847+  fd  Linux raid autodetect

Disk /dev/md0: 2047 MB, 2047934464 bytes
2 heads, 4 sectors/track, 499984 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk identifier: 0x00000000

Disk /dev/md0 doesn't contain a valid partition table

Disk /dev/md1: 2048 MB, 2048000000 bytes
2 heads, 4 sectors/track, 500000 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk identifier: 0x00000000

Disk /dev/md1 doesn't contain a valid partition table

Disk /dev/md2: 746.1 GB, 746057498624 bytes
2 heads, 4 sectors/track, 182142944 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk identifier: 0x00000000

Disk /dev/md2 doesn't contain a valid partition table

[root@cwilliams ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/md2              684G  796M  649G   1% /
none                  1.9G  112K  1.9G   1% /dev
none                  1.9G     0  1.9G   0% /dev/shm
/dev/md0              1.9G   46M  1.8G   3% /boot

Last edited by Carlwill (2009-10-30 14:18:26)

Carlwill · 2009-10-30 14:22:08

**Update**

That broke my system. I think I have exhausted all the time I am willing to waste on Arch with Software RAID. Good luck all!

Arch Linux

#1 2009-10-29 13:55:31

RAID1 Drive Removed?

#2 2009-10-29 14:41:04

Re: RAID1 Drive Removed?

#3 2009-10-29 14:45:21

Re: RAID1 Drive Removed?

#4 2009-10-29 14:57:45

Re: RAID1 Drive Removed?

#5 2009-10-29 15:01:15

Re: RAID1 Drive Removed?

#6 2009-10-29 15:21:37

Re: RAID1 Drive Removed?

#7 2009-10-30 00:51:50

Re: RAID1 Drive Removed?

#8 2009-10-30 14:15:57

Re: RAID1 Drive Removed?

#9 2009-10-30 14:22:08

Re: RAID1 Drive Removed?

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