HP XP P9500 Hitachi Dynamic Link Manager Software User Guide for VMWare (HIT52 - Page 26

Paths to Which Load Balancing Is Applied, When Using the Hitachi AMS/WMS Series

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Figure 2-6 Flow of I/O Data When the Load Balancing Function Is Used When the load balancing function is used, I/O operations are distributed via multiple paths (A, B, C, and D). This helps to prevent problems with system performance and helps prevent bottlenecks from occurring. Paths to Which Load Balancing Is Applied This subsection describes, for each type of storage system, the paths to which the load balancing function is applied. When Using the Hitachi AMS/WMS Series When HDLM performs load balancing, it differentiates between load balancing among owner paths and among non-owner paths. An owner path is a path that passes through the owner controller for a target LU. When you set up an LU, you have to specify which CHA to be used as the owner controller for the LU. Because different LUs might have different owner controllers, different LUs might also have different owner paths. A non-owner path is a path that passes through a CHA other than the owner controller. This type of CHA is also known as a non-owner controller. An owner path is usually used in preference to a non-owner path. In order to prevent system performance from slowing down, HDLM does not perform load balancing between owner paths and non-owner paths. If failures occur across some of the owner paths, 2-8 HDLM Functions Hitachi Dynamic Link Manager User Guide (for VMware(R))

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Figure 2-6 Flow of I/O Data When the Load Balancing Function Is Used
When the load balancing function is used, I/O operations are distributed via
multiple paths (A, B, C, and D). This helps to prevent problems with system
performance and helps prevent bottlenecks from occurring.
Paths to Which Load Balancing Is Applied
This subsection describes, for each type of storage system, the paths to
which the load balancing function is applied.
When Using the Hitachi AMS/WMS Series
When HDLM performs load balancing, it differentiates between load balancing
among owner paths and among non-owner paths. An
owner path
is a path
that passes through the
owner controller
for a target LU. When you set up an
LU, you have to specify which CHA to be used as the owner controller for the
LU. Because different LUs might have different owner controllers, different
LUs might also have different owner paths. A
non-owner path
is a path that
passes through a CHA other than the owner controller. This type of CHA is
also known as a
non-owner controller
. An owner path is usually used in
preference to a non-owner path. In order to prevent system performance
from slowing down, HDLM does not perform load balancing between owner
paths and non-owner paths. If failures occur across some of the owner paths,
2-8
HDLM Functions
Hitachi Dynamic Link Manager User Guide (for VMware(R))