Raid1 MDADM, root volume weirdness

Randall Slack · 02-26-2008, 11:06 PM

Welcome to LQ

hyuga · 07-24-2010, 08:10 AM

I found this thread while searching for the issue I am having. I think this is relevant to this discussion, but I do not think my problem is the same, because my setup has been running for a while (2+ years) without this problem.

The problem is that one of my RAID1 arrays is missing a partition:

Code:

md1 : active raid1 sda2[2](F) sdb2[1]
      2096384 blocks [2/1] [_U]     

md0 : active raid1 sda1[0] sdb1[1]
      193261824 blocks [2/2] [UU]

Initially I thought the drive was faulty and I just needed to exchange it. I've done this in the past on RAID5 arrays, so I thought it would be a quick swap.

However, I got confused when I checked the drive via smartctl and it passed. I then noticed that the other array for which this drive is part of was running fine.

Array details:

Code:

/dev/md1:
        Version : 00.90.03
  Creation Time : Mon Feb 18 20:37:06 2008
     Raid Level : raid1
     Array Size : 2096384 (2047.59 MiB 2146.70 MB)
  Used Dev Size : 2096384 (2047.59 MiB 2146.70 MB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Sat Jul 24 07:59:30 2010
          State : clean, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 1
  Spare Devices : 0

           UUID : d38ea776:cc395188:202c2b67:ab334dc5
         Events : 0.1060

    Number   Major   Minor   RaidDevice State
       0       0        0        0      removed
       1       8       18        1      active sync   /dev/sdb2

       2       8        2        -      faulty spare   /dev/sda2

Is this the same issue or at least related?

hyuga · 07-25-2010, 07:57 AM

After backing up essential file as a precaution, I performed a remove of sda2 from md1. Then I readded it back to the array and it promptly recovered! Still not sure why it was marked as faulty, but this seems to have fixed it.