Standardized Testing for SSD’s and HDDs

Performance and Reliability

IDEMA Technical Symposium May 2008

Ed DawsonFlexstar Technology

edawson@flexstar.comwww.flexstar.com

Agenda

Performance & Reliability Testing

• Why Test• What is Standardized Testing• Reliability & Performance Testing• Device Specific Tests• Storage Test Evolution

Why Test?

• Engineering Verification– EVT DVT etc– Development debug

• OEM Qualification– Systems qualification– Performance evaluation– Four corner testing– ORT

• Device Manufacturing– Meet specifications– Reliability / early life failures– Fast failure analysis

• Field– Failure analysis– RMA confirmation

Why Standardized Tests?

• Engineering Verification– EVT DVT etc– Development debug

• OEM Qualification– Systems qualification– Performance evaluation– Four corner testing– ORT

• Device Manufacturing– Meet specifications– Reliability / early life failures– Fast failure analysis

• Field– Failure analysis– RMA confirmation

Standardized Testing

Key Features of Standardized Testing• Accuracy• Repeatability

– Ability to reliably recreate same testconditions globally

• Tight control over test conditions– Environmental– Test tool environment

• Scripting Based Tests– Suits individual product requirements– Easily sharable

• Ability to debug in place– Interrogate / Trace failure conditions– Remote testing/debugging

• Provides Data Collection & Correlation– Consistency across the industry– Understandable Reports

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Test Points

Rate (KB/s) Performance

Stop the questioning & finger pointingby standardizing

The benefits of standardized, independent test systems– Standard test hardware– Unbiased and fair– Repeatable test solutions– Common test scripts– Industry standard interfaces– Correlation between

manufactures and EOM’s– Speeds failure analysis– Investment protection

Standards and Performance Testing

Storage Test Requirements

• Seek, transfer, & throughput performance• Interface verification• Specification compliance• Head-disk interface integrity• Media scans• Voltage margins• Long term reliability • Environmental & Edge case

Performance Testing

General Performance Testing– Seek & Transfer

• Sequential • Random• w/ & w/o compare• etc, etc…

– Multiple streams– Variable data stream width/ block

size, knee testing

Performance Testing

HDD Specific Performance Testing– Radial Performance– Seek mode performance

SSD SpecificPerformance– Fragmented Wear Leveling

Reliability Testing

Design & Manufacturing

Targeted test paths

Field & Reliability

Reliability Testing

HDD design verification / qualification( rotational media)

Test Process⇒Pattern reads/writes/verify⇒Power cycling⇒ Extended test at temperature⇒Voltage margining⇒Temperature Cycling⇒Voltage margining & 4 corner

Root Cause– Design/Components/DRAM

– Component Failures / i.e. red phosphorous

– Head/Media instability– Design margin

Reliability Testing

HDD variable field failure modes(variable factors in rotational media)

Root Cause– Contamination– Handling, head laps– Lube issues– Motor bearings– Growing defect lists

Test Process⇒ Multiple full media R/W.⇒ Head/Surface defects⇒ W/R adjacent tracks⇒ Dwell at elevated temperature

Reliability Testing

Root Cause– Endurance– Performance-mfg. variability– Bit failures / Data Retention– Component Failures / i.e.

red phosphorous– Write splice– Metadata corruption– Write performance– Erase failures– Design Margin

Test Process⇒ Multiple writes⇒ Performance verification⇒Disturb testing / pattern writes⇒ Temperature Cycling⇒ Voltage margining & 4 corner⇒ Power cycling mid writes⇒Random I/O w/ power cycling⇒Cold write⇒Margined erase⇒ Four Corners

SSD design verification / qualification

Reliability Testing

SSD testing for variable failures

Root Cause– Wear leveling performance– Data Retention– Reallocation errors

Test Process⇒ Fragmentation tests⇒Temperature & power cycling⇒ RW tests w/ power cycling⇒ Write splice, cold writes

Variable Failure Modes

Post Manufacturing Failure Modes

ODD• Media Failures• Motor Issues• Mechanical• Optical pickup

SSD• Endurance

HDD• Contamination• Handling• Head slaps• Lube Issues• Motor Bearings• Environmental

strains

AFR Predictions

Predicting a New ERA

• Historically, AFR cannot be correlated to manufacturing or line integration failure rates.

• AFR will be more predictable in SSD, primarily due to the eliminating of mechanical failures.

• Standardized front end testing for SSD's will lead to more a more reliable predicted AFR benefiting storage integrators.

SSD vs. HDD

What the Customer Expects(in a world of tests developed by key OEMs)

• Complete functional equivalence and independence.• Interface testing• Reliability demonstration• Performance demonstrations• Endurance demonstration• Power on / spin-up / sleep / resume from sleep

compliance.

Summary

What’s the role of organizations like IDEMA?

At a point where test standards can be developed for new solid state storage that are reflective of the technology.

Thank You

Ed Dawson, Flexstar Technology