Replace failed RAID drive

Posted on 2008-11-03
Last Modified: 2013-12-16
I have an old Redhat box running RAID 5. One of the drives failed and needs to be replaced.

I found instruction below on how to replace it but the instructions leave a few questions unanswered.

"3. Partition the new drive so that the partitions on it are identical to those on the other drive(s) in the array"
How do I do that?

"4. Issue the following command: raidhotadd <raid-device> <disk-partition>"
How do I find out what <raid-device> is and what <disk-partition> is?

Thanks. Rebuilding a RAID array with raidhotadd

Should /proc/mdstat show that a problem exists with one of the RAID arrays, the raidhotadd

utility program should be used to rebuild the array. Here are the steps that would need to be performed:

1. Determine which disk drive contains the failed partition

2. Correct the problem that caused the failure (most likely by replacing the drive)

3. Partition the new drive so that the partitions on it are identical to those on the other drive(s) in the array

4. Issue the following command:

raidhotadd <raid-device> <disk-partition>

5. Monitor /proc/mdstat to watch the rebuild take place. Here is a command that can be used to watch the rebuild as it takes place:

watch -n1 cat /proc/mdstat

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Question by:xy8088
    LVL 43

    Expert Comment

    Hmm, I usually do
    sfdisk -d /dev/currentMember | sfdisk /dev/newMember
    before You ask how You find current and new member refer next question

    cat /proc/mdstat # shows all software raids on Your system with members, pick the correct one (is should has failed disks).

    You can bring the content here so we'll try figure it out for You.
    LVL 3

    Author Comment

    Running "cat /proc/mdstat" gives me:

    Personalities :
    read_ahead not set
    unused devices: <none>
    LVL 43

    Accepted Solution

    Since You have no software raids defined, I suspect You have hardware raid implemented on the HW controller. Refer controller's guide then.

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