Apacer and Diskeeper Corporations - The Best Gets Better

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®Apacer and
®Diskeeper Corporation
The Best Gets Better® ®Apacer and Diskeeper Corporation-The Best Gets Better
Table of Contents
Overview 1The Problem 1Problem Analysis 1TThe Software Solution: HyperFast 2Summary 7
Disclaimer: Diskeeper Corporation is not responsible for the behavior or support of third party products mentioned in this document.© 2008 Diskeeper Corporation. All Rights Reserved. Diskeeper, Innovators in Performance and Reliability Technologies, HyperFast and InvisiTasking are either registered trademarks or trademarks of Diskeeper Corporation. Apacer is a registered trademark of Apacer Technology Inc. Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. All other trademarks are the property of their respective owners. Diskeeper Corporation . 7590 N. Glenoaks Blvd. Burbank, CA 91504 . 800-829-6468 . www.diskeeper.com® ®Apacer and Diskeeper Corporation-The Best Gets Better 3
Overview
This paper details the purpose and benefits of a ground-breaking technology alliance between NAND Flash hardware leader Apacer Technology Inc, and storage performance technology innovator Diskeeper Corporation.
The Problem
Solid State Drives (SSD) have several issues that come into play when used as the primary storage medium in place of traditional magnetic Hard Disk Drives (HDD); specifically regarding the operating system's logical file system. To date, file systems have been designed under the pretext of HDDs, and do not properly account for new NAND Flash / SSD technology.
This leads to issues that negatively impact mass market adoption of NAND Flash memory into the consumer, small/medium businesses, and enterprise markets where legacy file systems, designed for HDDs, will dominate the landscape for many years.
Problem Analysis
The principle issue is write speed degradation due to free space fragmentation. Small free spaces scattered throughout a volume at the logical level cause the file system to write a file in fragments to those small free spaces. This will degrade write performance as much as 80% to that solid state storage device. Fragmented free space forces the writing of blocks that are not advantageous to write or erase block boundaries, even if the application software would otherwise use large buffers.
Diskeeper Corporation has tested many current SSDs, from many manufacturers for file write speed degradation as a function of free space fragmentation. NTFS, the most common ®Windows file system by far, is shown to fragment free space rather aggressively over a few months and then grows slowly thereafter when not maintained (figure 1).
Fragmentation Levels(Free Space)
Figure 1: Accumulation of free space fragmentation through normal system use.® ®Apacer and Diskeeper Corporation-The Best Gets Better 4
Write performance decreases proportionately as free space fragmentation increases. The graph below (Figure 2) shows the resultant 80% write speed reduction on a variety of drives due to this effect. The test included copying a 1GB file on to an SSD with fragmented free space. The graph axis depicts the I/O write throughput in megabytes per second (MB/s) in relation to the number of file fragments the file is forced to be written in due to non-contiguous free space clusters. While a brand new SSD device may offer write performance in the 80 MB/s range to start, after a few weeks of use, performance will quickly deteriorate to 35 MB/s. Over the span of a few months, write speed becomes painstakingly slow at an abysmal 10 MB /s.
1GB File Write Test 32 GB SSD (PATA) 64 GB SSD (SATA1) 32 GB SSD (SATA2)90807060s/ 50BM 403020100084588458143101509615593162211678823328258533359336071457705320087386104024200398(128k)(64k)Number of Resulting File FragmentsFigure 2: Write I/O throughput degredation due to fragmented free space.
It is important to note that the performance loss due to fragmented free space affects all NAND Flash memory drives shipping today. The issue is not relegated to one specific vendor or other. The results depicted in Figure 2, for example, are non-Apacer devices.
TThe Software Solution: HyperFast
As described, the issue originates with how an operating system interacts with the storage hardware. The nature of modern operating sys... [download for more]