How can i monitor the raid-status (mdadm) ?

Tags: RAID, Software-RAID, mdadm, md0, degraded, raid1, active

When using a software RAID, it is necessary to check for proper functionality, since in case of failure, the redundancy is no longer provided by the RAID. An incomplete RAID should be completed and synchronized as soon as possible.

To perform a manual check, login to your server via SSH. You have two options to check the RAID state:

  1. Show the file /proc/mdstat .

    root@server:~# cat /proc/mdstat

    Personalities : [raid1]

    md0 : active raid1 sda2[0] sdb2[1]

    70337464 blocks super 1.2 [2/2] [UU]

    unused devices: <none>

    This shows which disks are in RAID (here: sda2 and sdb2). If a drive is not shown as "active" it is not part of the RAID anymore.

  2. Use the following command to get a detailed view of the RAID state.

    mdadm --detail /dev/md0

    (/dev/md0 may need to be replaced with the correct path to the device.)

 You can also setup mdadm to send you a mail if any issue with the RAID occours. For this you will have to adapt /etc/mdadm/mdadm.conf . Add the following line (replace e-mail address)

MAILADDR meine@adresse.tld

and restart mdadm

/etc/init.d/mdadm restart

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