1. LSI Logic Serial Attached SCSI (SAS) & SATA Overview

2. The Emergence of Serial Attached SCSI (SAS)
Newest Storage Interface for Direct Attach Storage (DAS)
SAS Improves & Builds on Parallel SCSI Foundation
Supported by ANSI T10 Standards Committee (Same as SCSI)
Successor to Ultra320 SCSI on Industry Roadmap
Significant Performance & Feature Set Enhancements
Source: SCSI Trade Association Jan 2004
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3. SATA vs SATA300 Feature Comparison
Feature List
SATA
SATA 300
First Party DMA 
Native Command Queuing
Identify device/set feature
Defect management
Enclosure management
Staggered Spin up
Hot Plug/Presence Detect
Port Multiplier 1.0
2nd Phy spec 3Gb/s
The Serial ATA native queuing model utilizes the First Party DMA mechanism to allow the device to select the appropriate host memory buffer to transfer data to or from.
New Serial ATA features and capabilities include a means by which their presence and support can be determined, and a means for enabling them if optionally supported.
Defect management, informative, SMART
drive staggered spin-up to minimize the power surge when a subsystem powers up.
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4. LSI Logic Storage Controllers
1H’05
3.0Gb/s
PCI RAID
HBA
FC 2Gb/s
FC 4Gb/s
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5. SAS is Compatible with SATA!
Feature: SAS controllers can talk to SATA or SAS HD Drives
SAS HDD - Used When Performance & Reliability are Critical
SATA HDD - Used When Capacity & Cost Are Most Important
SAS & SATA HDD - Can be Mixed in Single System
Benefit: Server & Workstation Platforms Can be Standardized to Reduce Component Qualification & Inventory
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6. SAS & SATA are Interoperable
SAS and SATA HDD connectors
SATA backplane connectors will NOT accept SAS HDDs
SAS backplane connectors accept both SAS target and SATA HDDs
Notch is filled in SAS connector
No Notch
Dual Ported
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7. New Terms SATA Architected, SATA Populated (SATA)
A system that contains SATA Controllers, SATA HDD, and optionally SATA Multipliers
Low cost, GREAT for certain markets (i.e. streaming, archive)
SAS Architected, SAS Populated (SAS)
A system that contains SAS controllers, SAS HDD, and optionally SAS expanders
X3 cost on HDD, top notch performance for IOP intensive applications
SAS Architected, SATA Populated (SAS/SATA)
A system that contains SAS controllers, SATA HDD, and optionally SAS expanders
This allows the creation of sophisticated topologies with low cost SATA HDD
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8. The Power of Serial Interfaces
SATA 300
SAS w/SATA HDD
SAS
Feature: Small Connector Enables Small Form Factor HDDs
Benefit: More storage per cubic inch 
Feature: Small Cable vs SCSI or ATA
Benefit: Simpler cabling, better cooling
Feature: 3 Gb/s (300 MB/s) ITransfer Rate Increasing to 12 Gb/s (1.2 GB/s) in Successive Generations
Benefit: Unprecedented performance and roadmap
Feature: Point to Point Connection with Dedicated Bandwidth
Benefit: Simplified cabling, NO signal integrity problems
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9.  SAS - SCSI on Steroids!! SATA SAS w/SATA HDD SAS
Feature: Full Duplex Data Transfer
Benefit: FC-like Simultaneous Upstream & Downstream Data Flow Effectively Doubling Performance 
Feature: Each HDD is Assigned a Unique World Wide Name (WWN), Similar to FC
Benefit: FC-Like SAN capabilities
Feature: Dual Ported
Benefit: FC-Like Redudancy
Feature: SCSI Tagged Command Queuing (256 Levels)
Benefit: Old fashioned SCSI performance, with all the benefits of SAS (SATA Native command queuing is GOOD, SCSI Command Queuing is better!!)
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10. SAS & SATA - The New Paradigm
SAS w/SATA HDD
SAS
Feature: SAS Supports up to 16,256 Devices in a Domain (128 is more practical)
Benefit: Sophisticated topologies including JBOD (SATA II = 15 Devices/ port) 
Feature: SAS Cabling Distances of 8m Point to Point (vs. 1m for SATA)
Benefit: Enables Box to Box connectivity within a Rack
Feature: SAS Expanders (vs SATA Multipliers)
Benefit: Allows Tremendous Flexibility in Application Configuration(i.e. JBOD and JBOD Cascading)
Feature: Wide Ports - Four Ports of Aggregated Bandwidth
Benefit: Unprecedented versatility in design and performance levels
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11. Technology Comparison
Significant
Differences Exist
SAS adds FC
Capabilities
SATA 300
SAS
Fibre Channel
Performance
Half-duplex
Full-duplex with
Link Aggregation
Full Duplex
3.0 Gb/s
3.0 Gb/s Introduction
6.0 Gb/s in 2006
2.0 Gb/s
4 Gb/s in 2004
Connectivity
1 m internal cable
> 8 m internal and external cables
15 m external cable (Copper)
Multipliers
15 HDD max
Expanders
>128 devices
127 devices FC-AL
16 Million Fabric
Availability
Single-port HDDs
Dual-port HDDs
Dual-port HDDs
Single-host
Multi-initiator
Multi-initiator
Driver
Model
Software transparent
with Parallel ATA
Software transparent
with Parallel SCSI
Software transparent
with Parallel SCSI
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12. SAS Expanders & Wide Ports Are Key!!
SAS Wide Ports are Unique in Storage
No SCSI, SATA, or FC equivalent
A wide port is defined as more than one physical link in a port
Wide ports are used to aggregate bandwidth
A wide port is a set of 1-4+ physical links between two devices. Different connections may be open on different links.
Typical usage: HBA/RAID controller wide port connected to expander wide port
All physical links in wide port use the same SAS address
Wide ports are transparent to the host/OS
Command sent down one link; data may be returned on another link (separate connection). No SW is required, all link arbitration is handled by HW.
SCSI Expert??
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13. The Real Power of Wide Ports
SATA Multiplier
SATA Multiplier
SAS Expander
Good for Streaming
Poor at IOPs
Good for Streaming
Good for IOPs
SATA Controller
SAS Controller
SAS Expander
X1, x2, x3, x4 Host Connection
ASx12 is 1x11, 2x10, 4x8
ASx28 and ASx36 coming
Streaming = Large Block Sequential
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14. SATA Multiplier vs SAS Expander
SATA HDD
SAS HDD 1 1 2 2 3
SATA HDD = 3 4 5
SATA Multiplier
Single Host Connection
Different chips for different HDD Counts
Vitesse 1x15
Silicon Image 1 x 5
SAS Expander
X1, x2, x3, x4 Host Connection
ASx12 is 1x11, 2x10, 4x8
ASx28 and ASx36 coming
LSI Logic, PMC Sierra, Vitesse
SATA Controller
SAS Controller
Note: ALL SATA FUNCTIONALITY IS CONTAINED WITHIN SAS
Except: SAS cannot talk to SATA multipliers
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15. Typical Configurations
Sample Configurations-Better than SCSI
^Clustered Solution
< Cascaded JBODs
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16. Standards & Initiatives
SAS Ecosystem
LSI
LOGIC
First Article Production
LSISAS1064
LSISAS1068
Controller Hardware
Expanders
LSISASx12
Vendor A
Vendor B
Vendor C
Vendor D
Hard Drives
SAS x1
SAS x4
Cables + Connectors
HBAs
RAID Controllers
Boards
Protocol Analyzers
Bus Exercisers
Jitter/Phy Analysis
Validation Equipment
Standards & Initiatives
SAS v1.0 Spec
STA Plug-Fest
Letter Ballot
INCITS Approved Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
2003
2004
2005
3/10/2004
LSI Confidential – Internal Use Only
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17. It’s REAL!! Learn About System Bandwidth
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18. The SAS Infrastructure

19. External 4X Connector
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20. SAS / SATA Multi-Lane Internal & SAS Multi-Lane External
(Drawing courtesy of Molex)
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21. SAS Multi-Lane Connections
(Drawing courtesy of Molex)
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22. New Connectors have been defined: SFF 8087 Internal SAS Connector
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23. SFF 8088 External SAS Connector
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24. SFF 8088 External SAS Connector
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25. Pieces of the puzzle Cables Chassis Technical Cable Concepts, Inc.
350 Lear Avenue, Costa Mesa, CA 92626
Casey Dugan (714) x135
Chassis
AIC
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26. Backup

27. SCSI - What If?? SCSI HDDs ( 1-15 HDD)
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28. Calculating System Bandwidth
~ 480 MB/s OR
~1000+ IOPS
4 300MB/s
1200MB/s
Large Block Sequential
HDD ~ 60MB/s
8 HDD = 480MB/s
Small Block Random
HDD ~ 120 IOPs &HDD Cache
8HDD ~ >1000 IOPs
PCIX 64b, 133MHz ~1000MB/s
PCIe ~ 250MB/lane
X4, X8, X16 common
8 300MB/s
2400MB/s
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29. SAS Protocols SSP - Serial SCSI Protocol
Used whenever SAS HDD talks to SAS Controller (with or without SAS Expanders)
SATA
Always used to communicate with a SATA HDD
STP - SATA Tunneled Protocol
Used when SATA HDD is connected to SAS controller via SAS expander
STP is used between SAS controller and SAS expander; SATA is used to talk to the SATA HDD
STP EMB (Enclosure Management Bridge), Allows a SAS controller to talk to the I2C interface embedded in the x12 Expander. Typically the I2C interface is connected to an external Enclosure Management Processor
SMP - Serial Management Protocol
Allows SAS controllers to configure SAS expanders
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30. Serial Protocols SSP STP SMP SSP or SMP EMB SSP I2C bus SATA SATA
LSI1068
SSP
STP
SSP
SMP
or SMP EMB
LSIx12
LSIx12
SSP
I2C bus
SATA
SATA
SAS
HDD
SAS
HDD
SATA
HDD
SATA
HDD
Enc.
Proc.
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