SSD and itsApplication in Enterprise

Storage

Frank Zhao

What’s SSD ? SSD (Solid State Drive): semiconductor-based block storage

device that appears to the host devices like a disk drive -IDC,2007

Other terms:

EFD (Enterprise Flash Drive, EMC) SCM (Storage Class Mem, IBM)

Types: DRAM + battery Flash based

NOR flash NAND flash

Why SSD ?Disk drive becomes the performance bottleneck!

Multiple core (Intel Nehalem)

DDR3-1333: 10GB/sQFI: 25.6GB/sPCIe*16: 8GB/sFC disk: 150MB/s!

Flash instead of spindle/platter NAND flash: high density, long endurance

Behaves like disk: Sector/page-based and well-suited for sequential data (pictures, audio,

and files) Bad block

Unlike disk : Wear out the cell

Two NAND types: SLC (single-level cell)

3X fast , 10X long endurance to MLC

MLC (multi-level cell) 2~3X more capacity than SLC

for enterprise

for consumer

NAND Flash internal

Data is grouped into block/page Page: 2K/4KB (plus spare area: 64B/128B) Block: 64/128 pages, up to 512KB

Special ops: Erase: set all bits within block to “1”

The smallest erasable entity is a block Program: change bit from “1”to “0”

SSD product Interface:

FC/SATA/SAS/ PCIe USB …

Property Performance Endurance Capacity Cost

SSD - PerformanceModel HDD

Intel X25-E

STEC ZEUSIOPS

Media TypeHDD15K

rpmSLC SLC

Capacity (GB) 600 64 73

User Space Rate -59.6/80

= 74.5%

73/128

=57%Cache (MB) 16 16 512

Access Time (ms) 3.4R 0.075,

W 0.0850.02~0.12

Sustained Read (MB/s)

147 250 220

Sustained Write (MB/s)

134 170 115

Random Read (IOPS)

250 35,000 46,000

Random Write (IOPS)

250 3,300 16,000

260XCache rate

30X ~ 170X

180X

60X

SSD: Endurance Data Retention:

10 years without power support MTBF

2 million hours (VS. HDD: 1.6million hours) Wear out

Limit cell write-cycle SLC 100K~1M writes MLC 10K writes

Available space is decreased: downgrade write performance when disk is nearly full

Solutions: Additional reserved space Wear leveling algorithm

to spread write across the whole disk Bad Block Management

map out the bad block

SSD: Capacity Amazing potential on capacity

Could be huge and costly 2.5 Inch: 512 GB 3.5 Inch: 1 TB (BitMacro)

Could be extremely small and inexpensive 4GB SSD for E-PC. Can you image a 10-$ HDD?

0.171.1

2.75

8.6

SATA FC MLC SLC

$/G

B

SSD: Cost

8X

2.48

0.03

FC SLC

$/IO

PS

83X

$ /GB $ /IOPS

SSD Cost: trend

1Q08 2Q08 3Q08 4Q08 1Q09

Cost/GB vsHigh Performance FC

≈40x

≈8x

≈22x

A brief summary

SLC NAND flash is dominant in enterprise environment Advantages:

Excellent performance for Read IO | Random IO | Small IO (<32KB) workload

Low power consumption Small size/weight

Limitations: Cost Endurance Performance downgrade

Alternate routes SSD as cache in server Standalone appliance Tired Storage

SSD in Enterprise Storage

Tired Storage

Cache

Standalone SSD array

SSD Application in Enterprise

BladeCenter HS21

2008 2009 20106

DS8000

3 9 63 9 12

ProLiant Blade, EVA

Blade/Server Unified Storage 7000 ZFS upgrade Storage F5100

USP V/VM

PAM(DRAM) RamSan on V3170

DMX-4 CX-4 2nd Gen SSD FAST

X/Blade/Power SVC

12

EMC

Strategic: Tiered Storage System EFD, FC, SATA

Products: V-Max/DMX-4: CX-4 Celerra

SSD Tuned Arrays will Totally Change the Game!

EMC-FAST (Fully Automated Storage Tiering)

Flash

Fibre Channel

SATA

Flash

SATA

Fibre Channel

V-LUN

V-LUN

Flash

Fibre Channel

SATA

FAST LUN level auto data movement, policy-based Management tools: Ionix (ECC), Navi, and RF

New Q4 2009

V-Max CX-4 Celerra

NetAPP PAM (Performance Acceleration Module)

PCIe card for read cache SW: ONTAP7G, FlexScale, and Predictive Cache Stat.

Add-on SSD array from TMS(Texas Memory Systems) Scale out the read performance for V-series/SAN SW: FlexCache

TMS RamSan 500: 2 TB, DRAM +flash array (RAID)

PAM1: DRAM, up to 16GB/card * 10

PAM2: SSD, up to 512GB/card * 8

SUN/Solaris “Hybrid Storage Pool”

Write IO: write-optimized SSDs (ZFS Intent-log) Read IO: commodity SSDs

Second-level flash cache (L2ARC) behind primary DRAM cache Smart replacement algorithm

18GB*8 100GB * 6

What’s Next in/after SSD? Views from array providers:

EMC: lower cost

IBM: MLC Revolutionary RAM tech?(Racetrack Mem, Phase Change Mem)

Micron, Samsung, Intel, Hynix Intel, JMicron, SandForce, STEC

STEC, Intel, Samsung, Pliant, Segate, Fusion-IO

SUN: MLC SW: to fault tolerant Distinguish write with read IO

Goal: Good Performance + Endurance + Capacity with affordable Cost

Chip Controller Drive

- 34nm- 3 bit MLC- Other NVRAM

- Write leveling algorithm- ECC/RAID/SMART/…- Bad blk map out- SLC+MLC+RAM

How to make best use of SSD?

What’s Next in/after SSD?