RAID 1 Degraded Array

gsoft · 08-18-2006, 05:19 AM

I have recently setup a RAID 1 Array, and have found that it is degraded/faulty not sure what this means exactly. What I want to know is how can I get it to be active and sync'ed. here are the details about the array.

cat /proc/mdstat

Code:

Personalities : [raid1]
read_ahead 1024 sectors
md0 : active raid1 scsi/host0/bus0/target0/lun0/part1[0]
      240832 blocks [2/1] [U_]

md1 : active raid1 scsi/host0/bus0/target0/lun0/part2[0]
      1951808 blocks [2/1] [U_]

md2 : active raid1 scsi/host0/bus0/target0/lun0/part3[0] scsi/host1/bus0/target0/lun0/part3[1]
      310375680 blocks [2/2] [UU]

unused devices: <none>

mdadm --query --detail /dev/md0

Code:

/dev/md0:
        Version : 00.90.00
  Creation Time : Sat Aug  5 07:27:41 2006
     Raid Level : raid1
     Array Size : 240832 (235.19 MiB 246.61 MB)
    Device Size : 240832 (235.19 MiB 246.61 MB)
   Raid Devices : 2
  Total Devices : 1
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Fri Aug 18 19:22:57 2006
          State : active, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 0
  Spare Devices : 0

           UUID : b8aafa16:58eacb39:759f2cd2:f0f9bafe
         Events : 0.53

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       0        0        1      faulty removed

Kernel: 2.4.27-2-386

I only noticed this because I keep getting an email once a day or so about it happening here is the email that is sent.

Code:

Subject: DegradedArray event on /dev/md1:debian

This is an automatically generated mail message from mdadm
running on debian

A DegradedArray event had been detected on md device /dev/md1.

I have been following this tutorial http://www200.pair.com/mecham/raid/raid1.html which has not helped much. Let me know if anymore information is needed.

acid_kewpie · 08-18-2006, 08:32 AM

well essnetially the second disk on both md0 and md1 is apparently shagged... as you're just on a mirror i would suggest that *IF* you have faith in the hardware, to add the device again using mdadm and let it remirror itself.

WhatsHisName · 08-18-2006, 02:17 PM

A better reference is the Software Raid HowTo: http://tldp.net/HOWTO/html_single/Software-RAID-HOWTO/

Your question is answered at the end of the “6.3 Simulating a drive failure” section: http://tldp.net/HOWTO/html_single/So...D-HOWTO/#ss6.3

The mdadm manpage has lots of good info, too.