EMC Symmetrix DMX-3, Product Manual

Page: 153 / 326

Software options overview 153
Performance and Optimization
Symmetrix
Optimizer Symmetrix Optimizer helps you increase the performance of a
Symmetrix system by spreading I/O activity evenly across the
physical disks. When a particular drive is in high demand, there is
excessive head movement on that drive. This movement slows down
read and write activity. By balancing highly active and less active
logical devices across drives, seek activity is balanced, and contention
among drives is reduced. Throughput within the overall Symmetrix
system is improved, and you experience optimal response times.
Optimizer performs self-tuning of Symmetrix data configurations
from the Symmetrix service processor by:
◆
Analyzing statistics about Symmetrix logical device activity.
◆
Determining which logical devices should have their physical
locations swapped to enhance Symmetrix performance.
◆
Swapping logical devices and their data using internal Dynamic
Reallocation Volumes (DRVs) to hold customer data while
reconfiguring the system (on a device-to-device basis).
How Symmetrix
Optimizer works
Symmetrix Optimizer:
◆
Automatically collects logical device activity data, based upon the
devices and time window you define.
◆
Identifies “hot” and “cold” logical devices, and determines on
which physical drives they reside.
◆
Compares physical drive performance characteristics, such as
spindle speed, head actuator speed, and drive geometry.
◆
Determines which logical device swaps would reduce physical
drive contention and minimize average disk service times.
◆
Using the Optimizer Swap Wizard, swaps logical devices to
balance activity across the back end of the Symmetrix array.
Optimizer is designed to run automatically in the background,
analyzing performance in the performance time windows you
specify and performing swaps in the swap time windows you specify.