HP Hitachi Dynamic Link Manager Software - Manual (Page 38)

2. HDLM Functions
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2.3 LU Configuration
After you have properly installed HDLM, the LU configuration will change as follows:
Before the installation of HDLM:
In the Windows' Disk Management window of a host, one SCSI device is
displayed as multiple LUs, each of which corresponds to one path.
In other words, the number of LUs in a storage system appeared to be the same as
the number of paths connected to the various SCSI devices.
After the installation of HDLM:
The MPIO driver combines what was once viewed as multiple LUs (each with
one path) into one LU containing multiple paths. In the Windows' Disk
Management window of a host, only the disks that have a one-to-one
correspondence with an LU in the storage system are displayed.
This means that each LU in the storage system is always recognized as only one
LU, regardless of the number of paths that are connected to SCSI devices.
You can display all the various SCSI devices from the Windows' Device Manager
window.
After the installation of HDLM, an LU recognized by a host is called a host LU (HLU).
The areas in a host LU that correspond to the Devs in a storage system LU are called
host devices (HDev).
On a system using HDLM, in order to access a target LU, a drive letter is first assigned
to the disk that has been integrated by the MPIO driver. Such disks are displayed in the
Windows' Disk Management window.
Figure 2-4: LU Configuration Recognized by the Host After the Installation of
HDLM shows the LU configuration recognized by a host, after the installation of
HDLM.