solving the i/o bottleneck with flash · conducted on dell latitude d420 notebook (intel core duo...

Santa Clara, CA USAAugust 2007 1

Solving the I/O bottleneck with Flash

Ori BalabanDirector of Sales for Global Accounts

SanDisk Corporation


Agenda

Performance bottlenecks in HDDAlternative solutionsSSD value proposition• Benchmark results

The future of SSD in notebook PCsSummary


Hard Disk Drives (HDD) evolution

New perpendicular technologyHigher capacities:• 40GB 1TB with multiple platters (mobile HDD 200GB)

Faster RPM:• 4200RPM 5400RPM 7200RPM ( 10k and 15k RPM

for enterprise)• Higher sequential transfers (MB/s)• But more power consumption

Lower cost per GB


Not all is Rosy for HDDs

HDD’s inherent mechanical design limits system performance improvements

WHY?


Terminologies: Random vs. Sequential

Random and sequential terms are used while discussing disk behavior Random activity means the disk accesses blocks from random locations on disk, usually incurring a time penalty while the disk heads seek and the disk itself rotatesSequential activity means the disk accesses blocks one after the other as they are located on the same sector


Windows Vista file transactions

Sequential read

Random read

Random write

Sequential write

20%

50%

20%

10%


Microsft VISTA Read data

0

1000

2000

3000

4000

5000

6000

7000

8000

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100 104 108 112 116 120 124 128

Buffer size [Sectors]

%

4KB size

Windows Vista file size


When Random and Sequential are used?

Random• OS changes and updates• Applications and documents

changes and updates • Access user data

Sequential• Boot• Hibernate• Application load (main file)

For example: When opening an application, the data files will be read in a sequential manner; however, all the associated DLL’s (~100 in average) will be read and loaded in random from 5-6 disk locations per DLL

Overall system performance is mainly dependant on random read performance (IOPS) rather than sequential transfers


Hard Disk Drive: Seek & Latency

When a request for data is issued, the drive head is most likelynot in the right place to read the data.The first step in retrieving the data is for the armature to move the head over the track where the data resides.The second step is for the disk drive to wait for the desired sector to rotate under the head so that the data can be read/written.

Seek

Latency

Seek

Latency


Result: slow random read on HDD

HDD transfer time = Interface transfer + media transfer + mechanical latency (in ms)Typical 4KB request:

5.4ms Total

Low IOPS limits system performance


How to solve the low IOPS problem?

System memory

Caching

SSD


Not all solutions are equally good

System memory:• Fast • Expensive • Limited capacity• Volatile

Caching:• Limited capacity • No proven value• Inherent HDD limitations• Not plug-n-play


Testimonials

“The hybrid hard drive concept works, and I believe that there is a lot of room for improvement, but I would not pay any premium today to get an H-HDD today. Performance-hungry enthusiasts should wait for decent Flash-only hard drives….”

Tom’s hardware July 13th, 2007

“But, in contrast, HP claims that Turbo Memory represents poor value for money and that it limits flexibility…”.

ZDNet June 4th, 2007

"There is no customer benefit right now [so] we decided not to integrate Robson and H-DD in the summer lineup [of new notebooks]…H-DDs are only available with 256MB integrated memory — too little to make a real difference. “

Sony to ZDNet, June 2007


SSD: No seek and latency


SSD offers high IOPS


IOPS SSD vs. HDD

Based on IOMETER 2003.12.16

5405.808215

1019.654617

7430.133983

53.91374467.09958667.5666460

1000

2000

3000

4000

5000

6000

7000

8000

0.5 1 2 4 8 16 32 64 128 256 512 1024

Transfer Size

IOP

S R

ead

SSD 2.5" SATA

SATA 7200 RPM

x80


PerformancePCMARK 2005Score for XP

Microsoft WEIScore for Vista

5.8

3.7

4.2

4.8

3

3.5

4

4.5

5

5.5

6

Vista WEI score

Scor

e

SSD 5000 1.8”/2.5”

HDD 1.8” 4200 RPM

HDD 2.5” 5400 RPM

HDD 2.5” 7200 RPM

9222

1225

31503805

310032003300340035003600370038003900310003

PC MARK HDD Score

Scor

e

SSD 5000 1.8”/2.5”

HDD 1.8” 4200 RPM

HDD 2.5” 5400 RPM

HDD 2.5” 7200 RPM


Vista User Scenario

10 sec 20 sec 30 sec

SSD 19

HDD

* HDD - 4200RPM, 60GB, 1.8”** SSD - SanDisk SSD UATA 1.8”

25

SSD 17

HDD 27

SSD

HDD

SSD

HDD

3.2

5.1

4.3

8.2

S4 - Resume

Shut down

2MB PDF

4MB PPT

31.5% faster

58% faster

59% faster

92% faster

Conducted on Dell Latitude D420 notebook (Intel Core Duo Processor ULV U2500, 1.20GHz, 533MHz, 1.0GB, DDR2-533 SDRAM)


User Scenario – boot and application launch

10 sec 20 sec 30 sec 40 sec 50 sec 60 sec 70 sec

Total: 65 Sec

BIOS OS boot Applications

11 Sec 37 Sec 17 Sec

10 Sec Total: 31 Sec12 Sec 9 Sec

Total: 50 Sec11 Sec 22 Sec 17 Sec

Total: 39 Sec10 Sec 20 Sec 9 Sec

XP Experience

Vista Experience

* HDD - SATA, 5400RPM, 80GB ** SSD - SanDisk SSD SATA 5000 2.5”

HDD*

SSD**

HDD*

SSD**

Conducted on Dell Latitude D620 notebook, (Intel Core 2 Processor T7200, 2.00GHz, 997MHz, 1.0GB RAM DDR2-533 SDRAM);


SSD offers more than performance Reliability

No failures from mechanical moving parts Enhanced user experience over HDDHigher MTBF** (6x) resulting in lower failure rates and much lower chances for data loss• 2M hours vs. 300K hours

Minimal support requests Highly durable:• Operating shock 1500G vs. 300G• Operating vibration 2.17G vs. 1.0G

• Up to 117% improved shock tolerance in operating mode

* HDD - MHV2080BH, 5400RPM, 80GB, SATA** MTBF is calculated based on

Parts Stress Method of Telcordia SR-332


Pow

er C

onsu

mpt

ion

(Wat

t)

Vendor

HDD* SSD**

5.5

2.4

0.60.3

0

1.0

0.4 0.3

Power Spin up Power Read/Write Power Idle Power Sleep

* HDD - ST10021AS, 7200RPM, 100GB, SATA

** SSD - SanDisk SSD SATA 5000 2.5”

No spin up powerHalf the power consumption during active operation~24 additional minutes on 4 hrs battery

SSD Lower Power ConsumptionLonger battery life Enhances user experience


The Future of SSD in PCs


0

1

10

100

2006 2007 2008 2009 2010 2011

($/G

B)

SSDNAND </= 1.0in HDD1.8in HDD2.5in HDD

Average Price per GB comparison, SSD, NAND and HDD by Form Factors, 2006-2011

Source: IDC, Worldwide Solid State Drive 2007–2011 Forecast and Analysis: Finding Space in the Expanding Digital Universe, Doc #207739, Jul 2007


Projected SSD Penetration in Notebooks by 2010

SSD penetration in ~20% of the notebook market = 32M unitsPenetration driven by elasticity and MLC adoption 1200 PB of NAND flash to be used in SSDs or about 11% of NAND outputTAM >$3B in 2010 $100/system ASP

0

5

10

15

20

25

30

35

2006 2007 2008 2009 2010

Units

(Mill

ions

)

0

200

400

600

800

1000

1200

1400

Meg

abyt

es (B

illio

ns)

Units MB

Source: Gartner, May 2007 Notebook market in 2010 is estimated at 153M units


Summary

Random drive transfer rates are key to improve PC system’s performance • IOPS and not sustained MB/s

SSD design needs to focus on random read transfers to offer better system performance Caching or memory system solutions do not provide suitable solutions for I/O bottleneck and as long as HDD is used, overall system performance will be limited by its inherent mechanical delaysPrice elasticity will drive higher penetration to the PC market


Thank You

solving the i/o bottleneck with flash · conducted on dell latitude d420 notebook (intel core duo...

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