Hitachi Dynamic Link Manager Software Users Guide for Linux (6.6) (HIT5203-96005, November 2011)

Restrictions on using HDLM in an IP-SAN environment
The following restrictions apply when using HDLM in an IP-SAN environment:
•
Use of HDLM in cluster configurations or boot disk environments is not
supported.
• The kdump function cannot be used.
LU Configuration
After you have properly installed HDLM, the LU configuration will change as
follows:
Before the installation of HDLM:
The host recognizes that a SCSI device is connected to each path.
Thus, a single LU in the storage system is recognized as though there are
as many LUs as there are paths.
After the installation of HDLM:
An HDLM device
corresponding one-to-one with an LU in the storage
system is created at a level higher than the SCSI device.
#
Thus, from the host, LUs in the storage system are also recognized as a
single LU regardless of the number of paths.
#
In addition to the one that indicates the entire LU, a logical device file
for the HDLM device is created for each partition.
An LU recognized by a host after HDLM installation, is called a host LU
(HLU).
The areas in a host LU that correspond to the Dev (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 SCSI device.
Figure 2-3 LU Configuration Recognized by the Host After HDLM Installation
on page 2-8
shows the LU configuration recognized by the host after HDLM
installation.
HDLM Functions
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Hitachi Dynamic Link Manager User Guide (for Linux(R))