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116 EMC Symmetrix DMX-3 Product Guide
Performance and Optimization
Overview
Real-world workloads consist of many different types of I/O activity.
They can be read or write requests, have different data block sizes, or
be skewed (some disks or host channels doing more work than
others). They can also be highly random, sequential, or mixed, and
they are often bursty (peak reads or writes can come at unexpected
times). The workloads used for envelope measurements are normally
static, simple, and designed to always yield certain levels of hit ratio
(access of read/write data directly out of global memory), regardless
of the global memory size and algorithms. In the real world, the
actual application behavior is greatly influenced by the performance
optimization algorithms.
Symmetrix Enginuity contains extensive algorithmic intelligence that
is designed to deliver fast application response time. These
algorithms optimize use of internal resources and allow end-user
definition of priorities for Symmetrix operations. These unique
algorithms balance the load evenly among Symmetrix components,
save valuable resources, and optimize data layout based on detection
of long-term workload patterns.
The Symmetrix DMX-3 offers improved performance over
conventional storage control units and DASD designs. The
Symmetrix features described in this section allow high global
memory hit ratios and less processing overhead, thus reducing
response time and improving throughput.
The Symmetrix Enginuity performance optimization features are
summarized in the following sections.