Create an mdadm software RAID level 1 (raid1)

Caution

This feature is available as Technology Preview. Use such configuration for testing and evaluation purposes only. For the Technology Preview feature definition, refer to Technology Preview features.

Warning

The EFI system partition partflags: ['esp'] must be a physical partition in the main partition table of the disk, not under LVM or mdadm software RAID.

During configuration of your custom bare metal host profile as described in Create a custom bare metal host profile, you can create an mdadm-based software RAID device raid1 by describing the mdadm devices under the softRaidDevices field in BaremetalHostProfile. For example:

...
softRaidDevices:
- name: /dev/md0
   devices:
   - partition: sda1
   - partition: sdb1
- name: raid-name
   devices:
   - partition: sda2
   - partition: sdb2
...

The only two required fields to describe RAID devices are name and devices. The devices field must describe at least two partitions to build an mdadm RAID on it. For the mdadm RAID parameters, see API: BareMetalHostProfile spec.

Caution

The mdadm RAID devices cannot be created on top of LVM devices, as well as LVM devices cannot be created on top of mdadm devices.

The following example illustrates an extract of BaremetalHostProfile with / on the mdadm raid1 and some data storage on raid0:

...
devices:
  - device:
      byName: /dev/sda
      wipe: true
    partitions:
      - name: root_part1
        sizeGiB: 120
    partitions:
      - name: rest_sda
        sizeGiB: 0
  - device:
      byName: /dev/sdb
      wipe: true
    partitions:
      - name: root_part2
        sizeGiB: 120
    partitions:
      - name: rest_sdb
        sizeGiB: 0
softRaidDevices:
  - name: root
    level: raid1  ## <-- mdadm raid1
    devices:
      - partition: root_part1
      - partition: root_part2
  - name: raid-name
    level: raid0  ## <-- mdadm raid0
    devices:
      - partition: rest_sda
      - partition: rest_sdb
fileSystems:
  - fileSystem: ext4
    softRaidDevice: root
    mountPoint: /
    mountOpts: "noatime,nodiratime"
  - fileSystem: ext4
    softRaidDevice: data
    mountPoint: /mnt/data
...

Warning

All data will be wiped during cluster deployment on devices defined directly or indirectly in the fileSystems list of BareMetalHostProfile. For example:

  • A raw device partition with a file system on it

  • A device partition in a volume group with a logical volume that has a file system on it

  • An mdadm RAID device with a file system on it

  • An LVM RAID device with a file system on it

The wipe field is always considered true for these devices. The false value is ignored.

Therefore, to prevent data loss, move the necessary data from these file systems to another server beforehand, if required.