HP Hitachi Dynamic Link Manager Software Licenses - Manual (Page 20)

What is HDLM?
With the widespread use of data warehousing and increasing use of
multimedia data, the need for high-speed processing of large volumes of data
on networks has rapidly grown. To satisfy this need, networks dedicated to
the transfer of data, such as SANs, are now being used to provide access to
storage systems.
HDLM manages the access paths to these storage systems. HDLM provides
the ability to distribute loads across multiple paths and switch to another path
if there is a failure in the path that is currently being used, thus improving
system availability and reliability.
The figure below shows the connections between hosts and storage systems.
A server on which HDLM is installed is called a host.
Figure 1-1 Connections between hosts and storage systems
For details about the storage systems supported by HDLM, see Storage
Systems Supported by HDLM on page 3-4 .
HDLM Features
HDLM features include the following:
The ability to distribute a load across multiple paths. This is also known as
load balancing.
When a host is connected to a storage system via multiple paths, HDLM
can distribute the load across all the paths. This prevents one, loaded
down path from affecting the processing speed of the entire system.
For details on load balancing, see
Distributing a Load Using Load
Balancing on page 2-10 .
1-2
Overview of HDLM
Hitachi Dynamic Link Manager (for Solaris) User Guide