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Paths to which load balancing is applied, Paths to which load balancing is applied -15, Not used – HP Hitachi Dynamic Link Manager Software User Manual

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Figure 2-8 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 Thunder 9500V Series, or Hitachi AMS/WMS series

HDLM performs load balancing between owner paths or between non-owner

paths. An owner path is a path that passes through the CHA. This path is set

on the owner controller of the storage system LU. Since the owner controller

varies depending on the LU, the owner path also varies depending on the LU.

A non-owner path is a path that uses a CHA other than the owner controller

(a non-owner controller). Paths used for load balancing are selected from

owner paths first, then non-owner paths. To prevent performance in the

entire system from deteriorating, HDLM does not perform load balancing

between owner paths and non-owner paths. When some owner paths cannot

be used due to a problem such as a failure, load balancing is performed

HDLM Functions

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Hitachi Dynamic Link Manager User Guide for Linux

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