Hitachi Dynamic Link Manager Software Users Guide for Linux

An md device created in HDLM cannot be used in a boot disk
environment.
If an md device has been applied to a directory that cannot be
unmounted while the system is operating (such as /opt, /tmp, or /var),
HDLM cannot be applied to that md device.
You cannot use the disk partition type RAID (fd).
In mdadm package versions 1.6.0-2 or earlier, you cannot manage
devices whose major or minor number is 256 or greater. Use mdadm
package versions 1.6.0-3 or later.
You cannot simultaneously specify SCSI devices and HDLM devices to
configure an md device. The following figure shows an example of when
SCSI devices and HDLM devices are simultaneously specified by mistake.
Figure 3-9 Example of Incorrectly Configured md Devices
If you want to manage md devices by using HDLM, migrate the md
devices that are made up of SCSI devices to the md devices that are
made up of HDLM devices. The following figure shows an example of
when this migration is performed.
Figure 3-10 Example of Correctly Configured md Devices
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Creating an HDLM Environment
Hitachi Dynamic Link Manager (for Linux®) User Guide