HP Hitachi Dynamic Link Manager Software - Manual (Page 31)

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:
The host recognizes that an sd or ssd device is connected to each physical path.
Thus, a single LU in the storage system is recognized as the same number of LUs
as that of physical paths.
After the installation of HDLM:
An HDLM device that corresponds one-to-one with the Dev in an LU in the
storage system is created above an sd or ssd device.
Thus, from the host, LUs in the storage system are also recognized as one LU
regardless the number of physical paths.
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 (slice or partition) in a storage
system LU are called host devices (HDev).
On a system using HDLM, the logical device file for the HDLM device is used to
access the target LU instead of the logical device file for the sd or ssd device.
The logical device files for sd or ssd are deleted by HDLM.
Figure 2-2: LU Configuration Recognized by the Host After the Installation of
HDLM shows the LU configuration recognized by a host, after the installation of
HDLM.