NEC Storage Performance Monitor/Optimizer User Manual page 88

Chapter 4 Overview of Performance Optimization Function
Optimization). By moving a logical disk, the arrangement of the Moved Material Logical Disk and the Work Disk for
Optimization is switched.
The logical disks are moved inside the disk array without affecting any business system. As a result, performance
tuning is possible while business is in operation. Transfer of logical disks will not require any changes of SG or
access methods to business systems.
High-load physical disk (= Bottleneck)
I/O concentrates in logical disks (LDx, LDy, LDz)
causing a high load state.
Exchange
Low-load physical disk
Due to performance tuning effect and so on, the performance optimization by the performance tuning function has
limitation. Logical disks cannot be moved in the cases described below. When you perform the tuning operation
or configuration setting of the disk array, please note the following:
*Cases in which logical disks cannot be moved
A Moved Material Logical Disk is located in the same RANK as a Work Disk for Optimization.
A Moved Material Logical Disk and a Work Disk for Optimization are different in capacity.
A Moved Material Logical Disk is a multiple RANK type.
A logical disk in which
I/O concentrates is
replaced with a work
disk.
Work Disk
Figure 4-2 Concept of Performance Tuning
II-6
I/O to LDx has been moved to the low-load physical
disk thereby canceling the high-load state.
Distribution of I/O cancels the bottleneck