I noticed a strange issue when creating RAID array with mdadm. As far as I see, it creates additional devices of
md type. According to the kernel.org documentation, the
md device type is Metadisk (RAID) devices.
The metadisk driver is used to span a filesystem across multiple physical disks.
However, this started to happens today on the same host. (I am using a configuration management tool to create a RAID array, but the same happens when I issue the mdadm commands manually.
lsblk output looks like below:
user@host:~$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT nvme0n1 259:0 0 1.7T 0 disk └─md0 9:0 0 3.5T 0 raid0 └─md0p2 259:2 0 1.8T 0 md xvda 202:0 0 20G 0 disk └─xvda1 202:1 0 20G 0 part / xvdf 202:80 0 20G 0 disk nvme1n1 259:1 0 1.7T 0 disk └─md0 9:0 0 3.5T 0 raid0 └─md0p2 259:2 0 1.8T 0 md
Can someone shed some light? Is this expected? I am seeing this for the first time.
Host is Ubuntu 16.04.6 LTS
Why are these created:
└─md0p2 259:2 0 1.8T 0 md