Now that we have a better understanding of RAID and the different configurations, let's go back to investigating our errors.
Apr 26 10:25:44 nfs kernel: md/raid1:md127: Disk failure on sdb1, disabling device. md/raid1:md127: Operation continuing on 1 devices.
From the preceding error, we can see that our RAID device is md127. We can also see that this device is a RAID 1 device (
md/raid1). The message stating Operation continuing on 1 devices means the second part of the mirror is still operational.
The good thing is that, if both sides of the mirror were unavailable, the RAID would completely fail and result in worse issues.
Since we now know the RAID device affected, the type of RAID used, and even the hard disk ...