ISS Technology Focus, Number 14

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ISS Technology Focus

Number 14

In this issue:

Choose the right solid-

state storage solution

Efficiency of DC vs. AC

power supplies

Tip: Check Hyper-

Threading status

remotely using

Microsoft® Windows®

PowerShell

Recent publications

ISS TechComm iTunes

New posts are now

available on Apple

iTunes, either check your

iTunes page or go to

ours: iTunes page.

Like us:

Choose the right solid-state storage solution

This article describes the features and applications of HP enterprise class solid-state

drives (SSDs) and IO accelerators. A subsequent article will detail the differences in these

solid-state storage devices based on performance, latency, lifetime writes, and expected

life at 100% writes. HP solid-state storage devices are based on NAND flash memory,

which is the predominant solid-state storage technology. Before describing the features

and applications of these devices, we must explain a few important characteristics of

NAND flash memory. If you are unfamiliar with NAND architecture, read the technology

brief “Solid state storage technology for ProLiant servers” at

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01580706/c01580706.pdf.

NAND flash memory

Solid-state devices based on NAND technology have a finite amount of writes and can be

„worn out‟ over time. The life expectancy (endurance) of a SSD or IO accelerator is

dependent on the NAND technology, write workloads, and the capacity of the device.

There are two primary types of NAND flash technology, each with different endurance,

performance, densities, and costs.

•

Single-level cell (SLC) technology works by storing one of two different charge states in

each cell, representing a single bit of information.

•

Multi-level cell (MLC) technology stores two or more bits in one cell. This allows each cell to

increase storage density by 100% or more. Two-bit MLC stores one of four different charge

states in a cell. Three-bit MLC stores one of eight different charge states in a cell.

As shown in Figure 1-1, SLC NAND has higher endurance, retention, and write

performance than MLC NAND. MLC technology is the dominant NAND technology used in

consumer products where cost is a primary factor. SLC-based SSDs provide the highest

performance and endurance for enterprise server storage. MLC-based SSDs provide a

lower cost per GB solution but have lower write performance and write endurance. MLC-

based SSDs are a good option for read-intensive application environments with limited

write requirements.

Summary of content (5 pages)

PAGE 1
ISS Technology Focus Number 14 In this issue: » Choose the right solidstate storage solution » Efficiency of DC vs. AC power supplies » Tip: Check HyperThreading status remotely using Microsoft® Windows® PowerShell » Recent publications ISS TechComm iTunes New posts are now available on Apple iTunes, either check your iTunes page or go to ours: iTunes page.
PAGE 2
Figure 1-1: SLC and MLC technologies have different endurance, retention, performance, density, and cost. HP Enterprise SSDs In addition to providing high performance, SSDs are far more robust that spinning media drives against high shock and vibration up to 1000G. HP enterprise class SSDs features are described below.
PAGE 3
Table 1-1. The application recommendations in the table are based on the differences in the performance, cost, and endurance of the HP solid-state solutions. Follow these recommendations to ensure that you choose the correct product. Table 1-1: Enterprise solid-state storage device classes Efficiency of DC vs. AC power supplies HP offers 1200 W -48 V DC Common Slot Power Supplies with 90% efficiency for our ProLiant DL360 G7, DL380 G6 and G7, and DL385 G6 and G7 servers.
PAGE 4
power to DC. The severity of the power loss depends on the equipment. DC power distribution improves safety, minimizes electrical losses, and improves data center efficiency. As shown in the previous figure, DC power is isolated from the 480 V AC supplied by the utility. This is much safer for personnel servicing equipment because arc flash is not a concern. DC power distribution also requires fewer conversions from the utility to the server components, which increases efficiency.
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Recent publications The following is a list of papers published since our last edition of the ISS Technology Focus.