The following devices can be used for the mirroring among servers.
Internal disks (hard disks, SSD)
RAID disks by RAID card also can be used.
Physical disks (RMDK), virtual disks (VMDK) in a VMware environment
virtio-SCSI devices and virtio block devices of the KVM guest
Block devices in a cloud environment (except an FJcloud-Baremetal environment)
Block storage provided by the OpenStack Block Storage service (cinder) in an RHOSP environment
Partitions in the above disks
For example, when the server has only one internal disk, use it for installing the OS, and make the partition created in a free space as a target of the mirroring among servers.
The following devices can not be used for the mirroring among servers.
External disk units (such as ETERNUS) in a physical environment
The disk already registered to the GDS class
The device whose compatible device name is not sdX or vdX, such as GDS volumes, GDS slices, and LVM logical volumes
