Seagate ST373207LC Optimizing Storage with SAS: Beyond the 10K Compromise (72K

Optimizing Storage With SAS: Beyond the

10K Compromise

Introduction

Enterprise storage is entering a new era of cost-effectiveness and efficiency, driven by the growing movement towards specialized

storage solutions. The value proposition of this application-focused storage is straightforward: Optimize price/performance by

matching the storage device to the specific characteristics (quantity, needed availability, etc.) of the data. Naturally, such an

approach requires multiple device types, each cost-effectively performing its respective storage duties.

Serial Attached SCSI (SAS) is a fundamental enabling technology in this specialization revolution, seamlessly integrating multiple

types of storage devices in one enterprise-class infrastructure.SAS compatibility with Serial ATA (SATA) makes it possible to deploy

both online (performance) disc drives and nearline (capacity) disc drives on a common SAS backplane in a single enclosure.

Coupling this cost-effective infrastructure with optimal online and nearline drives ensures maximum storage value.

Over the years, 3.5-inch 10K-RPM disc drives have performed admirably in a broad variety of storage applications. But now these

generalized, “jack of all trades” drives are being supplanted by more specialized, application-specific devices. Eclipsed in both raw

performance and price/performance by 15K-RPM SAS online drives (and soundly trounced in cost/GB by SATA nearline-ready

drives), 10K SAS drives are a costly compromise, out of place in today’s more efficient storage environment.

Bottom Line: 15K SAS Delivers More

While the factors underlying the outstanding efficiency of 15K SAS storage systems are noteworthy (and covered later in this

analysis), it is the significant real-world benefits these systems provide that compel immediate discussion.

A common SAS deployment might entail a 2U, 12-bay enclosure/rack space filled with 3.5-inch disc drives. In order to address both

online and nearline applications, the backplane would typically contain a mix of SAS drives and SATA drives. As shown below, the

superior speed of 15K SAS drives not only delivers faster throughput, it also frees up enclosure space for more nearline drives. The

net result is

(see table 1):

TP-543 • From: Global Product Marketing • September 2005

Technology Paper