HP XP7 Storage - Manual (Page 52)

For example, in a normal state, I/O operations are not performed on the
paths coming from the standby host in the cluster configuration or on non-
owner paths (that is, some of the paths that access a Thunder 9500V series,
or Hitachi AMS/WMS series storage system). Because of this, for the standby
host or for a host connected to non-owner paths, we recommend that you
use path health checking to detect errors. This enables the system to use the
most up-to-date path-status information when selecting the next path to use.
You can configure path health checking by using the Options window of the
HDLM GUI or by executing the dlnkmgr command's set operation. For details
on the Options window, see the HDLM GUI Help. For details on the set
operation, see set (Sets Up the Operating Environment) on page 6-16 .
Distributing a Load by Using the Dynamic I/O Path Control
Function
The result of using HDLM load balancing to distribute a load can be improved,
by applying the HDLM dynamic I/O path control function to the storage
system in which the dynamic load balance control function is installed.
What is the Dynamic Load Balance Control Function
In a system configuration in which multiple hosts and a storage system are
connected, the I/O processing load tends to concentrate on the controller of
the storage system, causing throughput performance of the entire system
decrease. The dynamic load balance controller function evaluates such load
statuses on the controller and prevents storage system performance from
decreasing.
The following is a list of the storage systems that provide the dynamic load
balance controller function and are supported by HDLM.
• Hitachi AMS2000 series #
• Hitachi SMS series #
• HUS100 series
#
For using the dynamic load balance controller function there are
restrictions on the versions of the microprograms you install. For details,
see the release notes of HDLM.
Dynamic I/O Path Control Function
In a storage system in which the dynamic load balance controller function is
installed, enable the dynamic I/O path control function to make the HDLM
load balancing effective.
When the dynamic I/O path control function is enabled, the controller
selected by the dynamic load balance controller function is recognized as the
owner controller. Other controllers are recognized as non-owner controllers.
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HDLM Functions
Hitachi Dynamic Link Manager (for Windows®) User Guide