Seagate ST973401SS High-Capacity RAID Revolution (94K, PDF)

High-Capacity RAID Revolution

Introduction

Two powerful forces are shaping today’s enterprise storage landscape: the pressure for greater efficiency and cost-

effectiveness, and the inexorable demand for more storage capacity. Reconciling these rival imperatives falls to IT managers,

who must balance upper management’s fiscal goals with a stringent mandate that IT deliver seamless performance, capacity

and reliability.

Conceptually, the path to more efficient storage is straightforward: Deploy multiple levels of storage to optimize

price/performance based on the specific characteristics (quantity, required availability, and so forth) of the data. Such a

specialized approach demands multiple device types, each cost effectively performing its respective storage duties.

Driven by dramatic growth in areal densities, the emergence of affordable disc drives offering vast capacities and high

performance was a watershed event in the evolution of enterprise storage. The low cost-per-GB of desktop-class Serial ATA

(SATA) drives has spurred development of a new class of RAID-based storage to serve high-capacity applications. High-

capacity, SATA-based RAID storage is key to making cost-effective storage for business applications a reality.

But for one glaring problem: most SATA drives are designed for the desktop, not RAID-based applications. While effective in

some low-end server environments with usage profiles that resemble those of desktop computers, these drives are

incongruous with enterprise storage duties. Lacking the high reliability and RAID-friendly integration features required by

capacity-intensive 24x7 applications, desktop drives are clearly not the storage panacea some hoped they might be.

Enter the new genre of high-capacity/RAID-optimized SATA drives—engineered for 24x7 operation and purpose-built to excel in

RAID environments.

Evolution of High-Capacity RAID

Born of necessity and fueled by skyrocketing areal densities, the movement towards high-capacity RAID storage quickly gained

traction in the enterprise because it held the promise of simultaneously cutting storage costs and improving data accessibility.

The burgeoning wave of voluminous, inexpensive ATA drives could serve capacity-intensive applications at significantly lower

cost-per-GB than SCSI/SAS drives, while delivering far faster data access than offline tape libraries.

Initial forays into high-capacity RAID storage met with mixed results, largely due to the unavoidable reliance on parallel ATA

drives. Hamstrung by the interface’s inherent limitations (poor throughput with multiple users, master/slave and termination

issues), IT professionals have nevertheless managed to achieve a modicum of success with low-end servers and RAIDs

equipped with ATA drives.

But it wasn’t until the arrival of SATA disc drives that high-capacity, RAID-based storage galvanized the enterprise market.

TP531.2 • From: Seagate Global Product Marketing • June 2006

Technology Paper