SSD Architectures - Flash Memory Summit

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SSD Architectures - Flash Memory Summit

SSD Architectures

Which One is Right For You?

Qing Yang, CTO

August 11, 2011

CONFIDENTIAL | © VeloBit, Inc. 2011


Option #1: Server-Attached SSD

• Pros

• Closer to server lower latency, higher IOPS

• Cons

• Data island difficult to manage and protect

• Sharing issues

• Product forms:

• PCIe SSD Cards

• x1-x32 lanes, 16GB/s

• Fully exploit parallelism of SSD

• SATA and SAS SSDs

• 3—6 Gbps

• Inexpensive & compact

• Compatible with storage interfaces

Page 2

Linux

LAN

UNIX MS

CONFIDENTIAL | © VeloBit, Inc. 2011


Option #2: SSD Appliances

• Pros:

• Relatively easy to add to

existing infrastructure

• Purpose-built system may

offer high performance

• Cons:

• Adds another box ($’s,

back-up, reliability, space,

power, cooling)

• Requires new data

management & DR

systems and processes

Page 3

LAN

Storage Area

Network

SSD NAS

Appliance

SSD SAN

Appliance

CONFIDENTIAL | © VeloBit, Inc. 2011


Option #3: SSD in Storage Array

• Pros:

• Minimal change to

existing storage

• Leverages existing data

management & DR

• Cons:

• Latency

• Distance from server =

network bottlenecks

• Protocol and context

switching overheads

• Higher $ per IOPs

• Data Tiering Challenges

Page 4

LAN

Storage Area

Network

SSD Tier

HDD Tier

CONFIDENTIAL | © VeloBit, Inc. 2011


Best Choice Depends on Priorities

The ideal solution should

Use low cost SSD hardware of your choice

Leverage existing storage investments, easy management

Be transparent to applications

Dramatically improve both READ and WRITE performance

Have high reliability and long endurance

You could use any of these solutions:

Server attached

SSD

No matter which

solution you

choose, all boil

down to one

thing:

Page 5

SSD in a storage

array

Storage Tiering

Storage

Hierarchy

SSD Appliances

CONFIDENTIAL | © VeloBit, Inc. 2011


Does Traditional Cache Work on SSD?

1. Cache concept has been

around for decades

2. Flash Memory is quite

different from RAM

Asymmetric

No in-place writes

Wear-leveling &

garbage collection

Write amplification

3. Performance drops when

device approaches full

utilization

4. New challenges require a

New Way of Thinking

Page 6

Speedup

18

16

14

12

10

8

6

4

Page/Buffer Cache Performance

Flash cache performance assuming empty SSD

Realistic Flash cache performance as SSD being filled

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Cache Utilization

CONFIDENTIAL | © VeloBit, Inc. 2011


Why and How Cache Works

Page 7

Temporal Locality

CONFIDENTIAL | © VeloBit, Inc. 2011


VeloBit Opens a New Dimension in Caching

Content Locality

Page 8

Making the best

Use of flash

physical

Properties

Temporal Locality

CONFIDENTIAL | © VeloBit, Inc. 2011


Great & Endless Opportunity

Content Locality

Page 9

Making the best

Use of flash

physical

Properties

Temporal Locality

CONFIDENTIAL | © VeloBit, Inc. 2011


The VeloBit Solution

SSD caches mostly READ data

Holds only copies of data

Commodity SSD

Block-level

Interface

PRIMARY STORAGE VOLUME

This volume can be SSD, HDD, or SAN

No change to this system

Block-level

Interface

Application

VeloBit

•Caching

•Data Compression

•Data Placement

Block-level

Interface

Server

Any Disk

(SAN, Direct-Attached or SSD)

VELOBIT SOFTWARE

Device Driver

Installs without pausing

application

Works with any block storage

devices

Up to 10x Reduction in

Storage Latency

Page 10 CONFIDENTIAL | © VeloBit, Inc. 2011


MySQL Performance Improvement

50,000

40,000

30,000

20,000

10,000

0

Page 11

Storage System Performance

SysBench, 800MB

*VeloBit uses 128MB of SSD (16%)

SATA HDD High-End PCIe SSD VeloBit + High-End

PCIe SSD

VeloBit +

Commodity SSD

SSD $’s $5,000 $5,000 $200

Software $’s $999 $999

∙ VeloBit is 3x faster than the current SSD performance leader.

∙ VeloBit enables use of commodity SSD.

∙ VeloBit used 84% less flash in this benchmark.

CONFIDENTIAL | © VeloBit, Inc. 2011

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