HP XP7 Storage - Manual (Page 17)

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 2-8 .
The ability to continue running operations between a host and storage
system, even if there is a failure. This is also known as performing a failover.
When a host is connected to a storage system via multiple paths, HDLM
can automatically switch to another path if there is some sort of failure in
the path that is currently being used. This allows operations to continue
between a host and a storage system.
For details on performing failovers, see
Performing Failovers and Failbacks
Using Path Switching on page 2-13 .
The ability to bring a path that has recovered from an error back online. This
is also known as performing a failback.
If a path is recovered from an error, HDLM can bring that path back
online. This enables the maximum possible number of paths to always be
available and online, which in turn enables HDLM to better distribute the
load across multiple paths.
Failbacks can be performed manually or automatically. In an automatic
failback, HDLM automatically brings a path back online on the host side
when the user has fixed the physical fault in the path.
For details on performing failbacks, see
Performing Failovers and
Failbacks Using Path Switching on page 2-13 .
The ability to automatically check the status of any given path at regular
intervals. This is also known as path health checking.
#
Detects path errors by checking the path status at regular intervals. This
allows you to check for any existing path errors and to resolve them
promptly and efficiently.
For details on setting up and performing path health checking, see
Detecting Errors by Using Path Health Checking on page 2-22 .
#
This is implemented by functionality provided by VMware vSphere ESXi.
Overview of HDLM
1-3
Hitachi Dynamic Link Manager (for VMware®) User Guide