We just had a failed disk in one of our backup storages.
Our monitoring tool shows that the failed disk happened to be the one used by OS.
When I logged in and checked the Debian server, I couldn't see any hardware raid for these disks, so it has to be a software raid.
You can use this command to get the list of software raid on the system:
One you have identified failed disk, use the following command to remove it from the software raid:
mdadm --remove /dev/md0 /dev/sda1
md0 is the RAID name and
sda1 is a member of the raid ( which has failed)
In my setup, disk
sda has 3 partitions:
sda5, so I repeat the above command to remove them all.
Now you can insert new disk to another slot ( if there is one available) and then mirror the same partition from a working disk (
sdb in this case).
The new disk will have a name, please check on your system.
sfdisk -d /dev/sdb | sfdisk --force /dev/sdc
Once we have mirrored the partitions, it's time to add them back to existing raid:
mdadm --add /dev/md0 /dev/sdc1
mdadm --add /dev/md1 /dev/sdc3
mdadm --add /dev/md2 /dev/sdc5
Check that it is working: