Re: Determining which drive failed in RAID 5 array

From: Daniel Buggie (buggie_at_best.com)
Date: 08/05/05

  • Next message: Smith, Albert: "RE: Determining which drive failed in RAID 5 array"
    To: General Red Hat Linux discussion list <redhat-list@redhat.com>
    Date: Fri, 05 Aug 2005 12:20:56 -0700
    
    

    On Fri, 2005-08-05 at 10:54 -0700, Brian D. McGrew wrote:
    > I've got a RAID 5 array with four drives in it. One of them is failed,
    > I look at /proc/mdstat and it shows me 4/3 [UUU_].
    >
    >
    >
    > How do I know which one is faied???
    >
    >
    >

    If you sent out the full output from that command that would have
    helped. However, a couple of things should tell you which one failed.

    /proc/mdstat should list out all the partitions currently in the RAID on
    the same line that identifies which device it is (md0, md1, etc.). If
    you know which devices should be there that should help.

    For example (on a RAID 1):

    # cat /proc/mdstat
    Personalities : [raid1]
    md0 : active raid1 sda1[0]
          15880128 blocks [2/1] [U_]

    I know that /dev/sdb1 was the other device, so I can work from there.

    Also mdadm --detail /dev/md[x] should be able to tell you as well.

    # mdadm --detail /dev/md0
    /dev/md0:
            Version : 00.90.01
      Creation Time : Tue Aug 2 01:30:19 2005
         Raid Level : raid1
         Array Size : 15880128 (15.14 GiB 16.26 GB)
        Device Size : 15880128 (15.14 GiB 16.26 GB)
       Raid Devices : 2
      Total Devices : 2
    Preferred Minor : 0
        Persistence : Superblock is persistent

        Update Time : Tue Aug 2 06:27:21 2005
              State : clean, degraded
      Active Devices : 1
    Working Devices : 1
      Failed Devices : 1
      Spare Devices : 0

        Number Major Minor RaidDevice State
           0 8 1 0 active sync /dev/sda1
           1 0 0 -1 removed
           2 8 17 -1 faulty /dev/sdb1
               UUID : 44fbd581:ccf5eb3c:db517a25:9b319c57
             Events : 0.799

    If you have rebooted though, this will probably all go out the window...
    since what was /dev/sdb will probably now be /dev/sda, etc.

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  • Next message: Smith, Albert: "RE: Determining which drive failed in RAID 5 array"

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