ENTERPRISE
SSDs

which induces suboptimal wear of the NAND and can vary dramatically by SSD vendor. Some SSDs have write-amplification penalties, which render the life of the drive 75 percent less than true enterprise-class SSDs, which have considerably more efficient write-amplification techniques.

The final facet of this SSD housekeeping process is that most SSDs in the market that are not optimized for enterprise applications suffer from performance problems, because the background NAND management process ultimately becomes a foreground bottleneck. The notebook class of SSD needs relief (in the form of idle time) from the heavy enterprise duty cycles in order to do the housekeeping of the NAND. Enterprise applications need drives

FIGURE
3
Power Comparison: Enterprise SSD
vs. Enterprise HDD

Enterprise HDD 7,200w

STEC Enterprise SSD 24.3w

to be poised for high performance 24/7 and thus cannot allow idle time.

Another important technique implemented in enterprise SSDs is the over-provisioning of NAND capacity, which is a vital means of achieving optimal performance and reliability. In the enterprise, there is no tolerance for varying performance in the drive. A drive cannot expect to have idle time available as a convenience to perform critical tasks. Having additional NAND within the drive will allow the drive to perform critical housekeeping tasks as background operations and then incorporate prepared blocks following background sanitization and preparation. When implemented properly, this technique significantly reduces write amplification and optimizes performance.

THE TECHNOLOG Y APPLIED IN AN
EN TERPRISE APPLICATION

While it is great to think through the sheer performance improvement of one drive technology versus another, let us now focus on the profound impact this has at the system level. Not only does SSD technology dramatically bolster system-level performance, but it also addresses one of the other most pressing issues in the data center: power reduction.

Enterprise-class SSDs present a compelling combination of performance and power savings that makes the technology a vital part of the storage technology spec-

FIGURE
4Performance Tiers for
Enterprise Storage Systems

storage controller with DRAM

tier 0 enterprise SSD

tier 1

fiber channel HDD

tier 2

tier 3

SATA HDD

tape/ offline

data storage aggregation,

redundancy/availability ultra high-performance storage systems by enterprise class flash techonology high-performance enterprise class HDD with fiber channel interface

low cost HDD storage

lowest cost storage media for archiving, backup, and off-line backup