Hitachi XP P9500 User Manual page 32

Hitachi dynamic link manager software user guide for aix (6.6) (t5208-96012, november 2011)
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The Extended Round Robin algorithm
The Least I/Os algorithm
The Extended Least I/Os algorithm
The Least Blocks algorithm
The Extended Least Blocks algorithm
The above algorithms are divided into two categories, which differ in their
processing method. The following describes both of these processing
methods:
The Round Robin, Least I/Os, and Least Blocks algorithms
These algorithms select which path to use every time a certain number of
I/Os are issued. The path that is used is determined by the following:
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The Extended Round Robin, Extended Least I/Os, and Extended Least Blocks
algorithms
These algorithms determine which path to allocate based on whether the
data of the I/O to be issued is sequential with the data of the I/O that
was issued immediately beforehand.
If the data is sequential, the path used will be the one to which the data
of the I/O that was issued immediately beforehand was distributed.
However, if a specified number of I/Os has been issued to a path,
processing switches to the next path.
If the data is not sequential, these algorithms select the path to be used
each time an I/O request is issued.
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Table 2-4 Features of the Load Balancing Algorithms on page 2-13
the features of the load balancing algorithms.
2-12
Round Robin
The paths are simply selected in order from among all the connected
paths.
Least I/Os
The path that has the least number of I/Os being processed is
selected from among all the connected paths.
Least Blocks
The path that has the least number of I/O blocks being processed is
selected from among all the connected paths.
Extended Round Robin
The paths are simply is selected in order from among all the
connected paths.
Extended Least I/Os
The path that has the least number of I/Os being processed is
selected from among all the connected paths.
Extended Least Blocks
The path that has the least number of I/O blocks being processed is
selected from among all the connected paths.
HDLM Functions
Hitachi Dynamic Link Manager User Guide (for AIX(R))
describes

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