Micron Technology, Inc. · NASDAQ:MU
Micron Technology — Flash Memory Summit 2008
26 slides from Micron Technology's conference presentation, August 2008
Slide 1: SSDs: A Shift in Data Storage
SSDs A Shift in Data Storage Todd Dinkelman Micron Technology, Inc. Santa Clara, CA USA August 2008 1
Slide 2: Agenda
Agenda SSD Defined Quick Comparison Why MLC Reliability/Endurance Summary Santa Clara, CA USA August 2008 2
Slide 3: What is Being Called an SSD?
What is Being Called an SSD? USB interface embedded solution Module-based IDE interface card w/o enclosure 1.8-inch and 2.5-inch, 32GB and 64GB SSD for notebook and performance computing Module/card with custom form factor, density, and interface Santa Clara, CA USA August 2008 3
Slide 4: The Complexity of HDDs
The Complexity of HDDs Cover mounting holes Base casting HDD Advantages Spindle • Density • Price/GB Slider (and head) Actuator arm Platters Actuator Flex circuit SATA interface (attaches heads connector to logic board) Power connector Source: Panther Products Actuator axis Santa Clara, CA USA Aug
Slide 5: The Simplicity of SSDs
The Simplicity of SSDs SATA interface connector SSD Advantages • Performance • Size • Weight • Ruggedness • Temperature Range • Power NAND Printed Circuit Controller Santa Clara, CA USA August 2008 5
Slide 6: SSDs vs. HDDs
SSDs vs. HDDs Due to recent advances SSDs HDDs in NAND lithography, SSD densities have Capacity 9 reached capacities for Performance 9 mass market appeal Reliability 9 SSDs offer many Endurance 9 9 features that lead to Power 9 improved user experiences Size 9 Weight 9 Early shortcomings Shock
Slide 7: SSDs in Computing
SSDs in Computing CPU Relative Relative Latency Cost/Bit 1 L1 Cache 1,800 2.5 L2 Cache 1,400 1,200 DRAM 10 NAND 25,000 SSD 3 25,000,000 HDD 1 NAND Flash closes the latency gap Santa Clara, CA USA Cost/bit data as of November 2007 August 2008 7
Slide 8: NAND in Computer Architecture
NAND in Computer Architecture CPU DRAM Memory DRAM DDR3 & Bus PCIe Graphics Control Link Peripheral USB USB & Bus PCIe NVMHCI Flash Drive Control Flash SATA Hybrid SSD HDD Santa Clara, CA USA August 2008 8
Slide 9: MLC and SLC Differences
MLC and SLC Differences SLC • Single-level cell – One bit per cell MLC • Multi-level cell – 2 bits per cell – today – 3 and 4 bits per cell – future Endurance • SLC is typically 10 times better than MLC Performance • SLC provides ~2X the write performance of MLC Price • SLC-based products
Slide 10: SSD Market Trends
SSD Market Trends Improvements in controller technology • Moving from CompactFlash architectures to true SSD controllers Notebooks and PCs • Migration to MLC – Light usage model – Cost, size, and performance are all important • Value Proposition – Better than desktop performance in an ultra-ligh
Slide 11: SSD Average Price/GB
SSD Average Price/GB 1.8" HDD MLC SSD $/GB 2004 2006 2008 2010 2012 2014 Santa Clara, CA USA August 2008 11
Slide 12: NAND Reliability and Endurance
NAND Reliability and Endurance Effect Description Observed As Management Cells not being programmed Increased read Program ECC and Block receive charge errors immediately Disturb Management via elevated after programming voltage stress Cells not being Reliability read receive Increased read Read ECC
Slide 13: NAND Error Rate
NAND Error Rate Bit Error Rate – Failing bits corrected with appropriate levels of ECC – Correctable bit errors do not result in data loss Raw Bit Error Rate (RBER): Bit error rate prior to ECC Uncorrectable Bit Error Rate (UBER): Bit error rate after ECC UBER is projected using the measured
Slide 14: SSD Reliability and Endurance
SSD Reliability and Endurance SSD reliability has two parts • MTBF – Measure of time between failures due to manufacturing or component defects – 2 million hours is typical for Micron SSDs • Endurance – SSDs all wear out due to data writes – Indication of drive life based on a usage condition – Mi
Slide 15: Endurance Factors
Endurance Factors Wear-leveling efficiency Write amplification NAND cycles SSD densities Santa Clara, CA USA August 2008 15
Slide 16: Wear-Leveling
Wear-Leveling Dynamic wear-leveling uses the available free space and the incoming data to equally wear each of the physical blocks • Static data is not included in the available pool of wear-leveling blocks, leaving a portion of the drive with no wear Static wear-leveling considers all physical
Slide 17: Wear-Leveling Example
Wear-Leveling Example MLC devices can typically support 10,000 cycles per block If you erased and reprogrammed one block every second, you would exceed the 10,000 cycling limit in just 3 hours! 60 x 60 x 3 = 10,080 Rather than cycling the same block, wear-leveling involves distributing the num
Slide 18: Wear-Leveling Example (continued)
Wear-Leveling Example (continued) An 8GB MLC-based SSD contains 32,768 independent blocks (each block is 256KB of data) If we took the previous example and distributed the cycles over all 32,768 blocks, each block would have been programmed once after 9 hours If you provided perfect wear-level
Slide 19: Write Amplification
Write Amplification Additional write overhead due to garbage collection and wear-leveling • Write Amplification = Flash Writes / Host Writes Influence on host data patterns • Large number of small random transfers increases write amplification Influenced by number of spare blocks and static da
Slide 20: Typical PC File Transfers
Typical PC File Transfers Avg. Disk Bytes Per Read/Write 1800 1600 1400 1200 1000 800 Reads Writes 600 400 200 0 Less than 4KB to 16KB to 32KB to 64KB to 128KB to Greater 4KB 16KB 32KB 64KB 128KB 256KB than 256KB Transfer Size Santa Clara, CA USA August 2008 20
Slide 21: SSD Endurance Calculation
SSD Endurance Calculation Write amplification and wear-leveling efficiency must be accounted for when calculating SSD lifetime NAND Cycles * SSD Capacity Life in Years = Amplification Factor * GB/Year Santa Clara, CA USA August 2008 21
Slide 22: SSD Lifetime
SSD Lifetime Given a capacity point, NAND endurance, and writes-per-day, the upper limit on SSD lifetime is defined • Example: A 64GB SSD, 10K PROGRAM/ERASE cycles and write duty of 350 GB/day will wear out in 5 years Uneven wear within a NAND Flash device may cause ‘hot spots’ • Wear-leveling o
Slide 23: SSD Endurance
SSD Endurance Average Number Of Times Per Day The Drive Space Gets Written 60 50 33% WRITEs 2K random IOPs Times per Day (Count) 40 64GB drive 30 (55GB user-accessible 20% reserved spares 20 10 0 0 12 24 36 48 60 72 84 96 Required Lifetime (Months) Santa Clara, CA USA August 2008 23
Slide 24: SSD Capacity Effect on Endurance
SSD Capacity Effect on Endurance Years for SSD to Wear Out Time to Failure 32 64 128 256 512 Drive Capacity (GB) SSD life will double with every doubling of capacity Santa Clara, CA USA August 2008 24
Slide 25: Summary
Summary SSDs bring many advantages to storage • Performance • Power • Reliability • Environmental ruggedness Different products for different markets • MLC-based SSDs for PCs Reliability has two aspects • Endurance and MTBF Santa Clara, CA USA August 2008 25
Slide 26: Thank You
Thank You Santa Clara, CA USA August 2008 26