SAS Technology and Application Trends

Kevin Gray Maxtor Corporation 333 South Street, Shrewsbury MA 01545-4171 Phone: +1-508-770-6862 FAX: +1-508-770-299 E-mail: [email protected]

Presented at the THIC Meeting at the Sony Auditorium, 3300 Zanker Rd, San Jose CA 95134-1940 April 19-20,2005 Agenda

• Storage Application Trends • The Advantages of Serial Technologies • Serial Attached SCSI & Serial ATA Technology Overview • The Benefits of Serial Attached SCSI • Summary & Q&A

2 Storage Application Trends

3 Regulatory Shifts Effecting Storage

• New data storage rules are driving storage requirements – Retained for longer time – Rapidly accessible

–MarketMultiple sourceRegulations access Requirement

Financial services Basel 2 Accuracy, retention, retrieval and archiving of electronic SEC 17a – 3&4 records

Healthcare HIPAA, JCAHO, ISO Mandates disaster recovery and data back-up plans, enforces 17799 authentication and encryption of patient records

Life Sciences & FDA 21 CFR Part 11 Dictates how records are retained, shared and exchanged Pharmaceutical

Government DOD 5015.2 Must use DoD-compliant software and hardware agencies Public companies EU Data Protection Companies must ensure personal data is properly managed Directive in accordance with regulatory requirements. Sarbanes-Oxley Act of Managers must vouch for internal controls on transactions, 2002 digital information and communications 4 Pools of Storage

Cost of ownership has become an operations and infrastructure challenge

Transactional Reference Data Staging and Archive spooling

IT Managers are increasingly viewing data resources as “Pools of Storage” with differing characteristics to meet a range of application requirements

5 HDD Design Tradeoffs

7200 RPM 10K RPM 15K RPM Disk Drive Disk Drive Disk Drive

• Larger media increases • Smaller arm lowers • Larger magnets capacity but limits mechanical inertia to improve seek time rotational frequency reduce seek time ¾ Lower rotational frequencies moderate power consumption & improve rotational stability • Smaller media reduces seek distance

IOPS = 1/(seek time + average rotational latency + processing time)

6 ATA Share of the Enterprise

Worldwide Forecast of ATA HDD Share of Enterprise Apps

100%

80%

60%

40%

20%

0% 2004 2005 2006 2007 2008

Enteprise PATA/SATA Desktop PATA/SATA SCSI/SAS/Fibre

Source: Maxtor Corporation 7 The Advantages of Serial Technologies

8 “The World is Becoming Serial”

Consumer Electronics Computer Storage 1394, USB, Infrared Printers, Scanners, & SATA, SAS, FC, other Peripherals 1394 & USB USB PC Expansion PCI-Express Communications Networking Wireless, Telephone, Ethernet Digital Cable

• Serial interconnects are becoming widespread in our digital world, enabled in computing, communications & entertainment products • As silicon integration levels and bandwidth requirements increase, serial technology becomes more cost effective at shorter distances

9 Clock Skew Limits Bandwidth

• With a parallel , all data must be arrive within in a given time period • Signal skew causes data to become misaligned in time at the receiver limiting the rate at which data can be transferred • Serial technologies uses a single data line so there is no skew • With serial technologies, much higher data transfer rates can be obtained per signal line

Clocked Data Serial Data In

Clock Recovery Recovered Clock Circuit All bits are aligned at Skew causes transmitting device misalignment at the receiver Serial Data Transfers Parallel Data Transfers

10 Cross Talk

• Cross talk is an electromagnetic coupling that occurs between signal lines running in parallel to one another – Cross talk degrades the signal quality of adjacent signal lines. – Cross talk increases with the frequency of the data • Serial technologies do not require signal lines be run in parallel to minimize data skew • With fewer signal lines and no requirements for those lines to be run in parallel, cross talk is significantly reduced with serial architectures

Example of Cross Talk

Electromagnetic Coupling

11 Impedance Discontinuities Limit Bandwidth

Transmission Line Reflections

SCSI Device Connection

SCSI Stub creates Termination impedance discontinuity

Without • Beyond U320 SCSI, transmission line Impedance Discontinuity reflections on the parallel bus become more difficult to manage as data rates increase • Serial technologies eliminate impedance discontinuities due to transmission line With stubs by using point-to-point Impedance connections Discontinuity 12 Fewer Signal Lines

• As server form Parallel Serial factors shrink Cables Cables – Cabling becomes more difficult – become harder to route – Small Form Factor HDDs are used to improve IOPs while reducing power Photos courtesy of Intel and space requirements • Serial technologies require less signal lines – Creating thinner cables to ease cable routing

– Reducing routing SFF HDD with complexity SAS Connector – Enabling the use of smaller connectors with SFF HDDs SFF HDD with SCSI Connector 13 Parallel & Serial SCSI Comparison

Smaller Die Size & Reduced Pin Count Constrain Costs U320 SAS 3Gb Die Comparison

Signal Pins Signals+Power+Grounds Signals+Power+Grounds (Package/cost,routing =~80 Pins =~12 Pins congestion) Silicon cost Larger Die Area Smaller Die Area

Power Approx. 1.2 Watts Approx. 0.6 Watts

Performance 320 MB/sec. Peak 1200 MB/sec. Peak Bandwidth Bandwidth Single port, Half duplex Dual port, Full duplex 14 Serial Attached SCSI & Serial ATA Technology Overview

15 Interface Transitions

HDD Interfaces Are Moving From Parallel to Serial Architectures

Parallel ATA

Parallel SCSI

16 What Makes an Industry Standard?

Members of T10 Standards Committee

Storage Providers and Component/Infrastructure Drive Manufacturers

17 What is Serial ATA?

• Four-wire replacement for the physical layer of parallel ATA – 100% SW compatible replacement for ATA – Low voltage (600 mV max) w/ 8b10b encoding • “Star” topology (point-to-point, no hubs) – Each device gets full bandwidth – No bus arbitration/collision overhead HDD – ATA RAID becomes simpler to implement • Serial ATA has attributes and features that Host/RAID extend its capabilities Controller HDD

– Provides additional capabilities such as hot Each host port connects plug and 1st party DMA to only one HDD HDD

SATA connector drawing courtesy of Molex

18 What is Serial Attached SCSI?

• Four-wire replacement for the physical layer of parallel SCSI – SW compatible replacement for parallel SCSI – Low voltage (1600 mV max) differential signaling w/ 8b10b encoding • “Star” topology (point-to-point, no hubs) – Each device gets full bandwidth – Minimum arbitration overhead • SAS has attributes and features that can extend it beyond the capabilities of parallel SCSI

– Provides many additional Sys stem Bac superset features (such as kpl lane dual-port and 16K devices

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P S

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l on ing S C SATA devices in SAS ort systems P -OR -

19 Where Does Serial Storage Fit?

Servers SAN SAS or SATA Storage OPEN OPEN OPEN OPEN OPEN OPEN OPEN

Disk Interface OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN

Fibre Channel, , OPEN OPEN OPEN OPEN OPEN OPEN OPEN Infiniband, iSCSI SAN Infiniband, iSCSI SAN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN

Serial Attached SCSI z z

UPS Cabinet Interface UPS Where Do SAS and SATA Fit? SAS and SATA Direct Attached Direct Attached … Behind the Network! or Fibre Channel JBOD Storage RAID Storage Disk Interface OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN • Serial Attached SCSI and Serial ATA are storage, OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN not networking interfaces OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN • Lower cost of implementation OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN NAS OPEN OPEN OPEN OPEN • Reduced complexity to improve z z z z Storage UPS UPS UPS UPS interoperability • Support for a broad range of disk drives OPEN OPEN OPEN OPEN OPEN OPEN OPEN SAS or SATA Disk Interface OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN Workstations OPEN OPEN OPEN OPEN OPEN OPEN OPEN

Ethernet LAN Ethernet OPEN LAN z UPS

SAS or SATA SAS and SATA Disk Interface Or Fibre Channel Disk Interface 20 HDD Interface Comparisons

SATA SAS Fibre Channel Arbitrated Loop Half-duplex Full-duplex with Full Duplex Link Aggregation Performance 1.5 Gb/s Introduction 3.0 Gb/s Introduction 2.0 Gb/s 3.0 Gb/s in 2005 6.0 Gb/s in 2007 4 Gb/s in 2005 1.5 m internal cable > 8 m internal and 15 m external cable > 8 m external cable external cables

Connectivity One device >128 devices 127 devices (16,384 max)

No peer-to-peer Peer-to-peer Peer-to-peer Single-port HDDs Dual-port HDDs Dual-port HDDs Availability Single-host Multi-initiator Multi-initiator

Driver Software transparent Software transparent Software transparent Model with Parallel ATA with Parallel SCSI with Parallel SCSI

21 SCSI Trade Association Roadmap

SerialSerial Attached Attached SCSISCSI Serial Serial SASSAS 12Gb/s 12Gb/s AttachedAttached SCSI SCSI SerialSerial Attached Attached SASSAS 6Gb/s 6Gb/s SCSISCSI SASSAS 3Gb/s 3Gb/s

U640 has been removed from the SCSI Trade Association road map. ParallelParallel SCSI SCSI U320 will be the last enhancement to the Parallel SCSI interface, followed UltraUltra 320 320 by SAS

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

22 SAS/SATA Compatibility

• SAS Initiation Sequence Establish – Expander identifies device as SAS or connection Establish with expander connection SATA HDD using OOB using STP with drive – Expander negotiates transfer speeds SAS using SSP with HDD • Transmit and receive voltages are set during Controller speed negotiation – Expander communicates the type of Exchange • Communicates Exchange HDD interface (SAS or SATA), SATA • interface type SSP negotiated speed, and routing FIS’s with • transfer speed frames information to the SAS controller for drive • routing info with drive each attached HDD • Controller communicates with HDDs SAS through expander – The SAS controller exchanges frames Expander (SCSI commands, data, etc.) with SAS • Identify • Identify HDDs through the expander using Device as Device as Serial SCSI Protocol (SSP) SATA HDD SAS HDD – The SAS controller establishes • Negotiate • Negotiate connection with SAS expander using Speed Speed Serial ATA Tunneling Protocol (STP) – The SAS controller exchanges SATA SATA SAS FIS’s with with SATA HDDs HDD HDD 23 Device & Backplane Connectors

SAS and SATA device connectors

SAS backplane connectors accept both SAS target and SATA device connectors (SATA backplane connectors will not accept SAS target connectors)

24 SAS Direct Cable Configuration

25 SATA2 & SAS Backplane Configuration

26 SAS Redundant Backplane Configuration

27 External Cable and Connector

(Photo courtesy of FCI/Berg)

• Four, full-duplex physical links per connector •4 × 2 × 3.0 Gb/s = 24 Gb/s = 2,400 MB/s max

28 The Benefits of Serial Attached SCSI

29 Serial Technology Enables Choice

One backplane accommodates either SAS or SATA HDDs

Sys r tem

o B

t ac k c pla S n

e e

A

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Atlas 10K and/or Atlas 15K SAS MaXLine Drives SATA Drives

• High-performance & highly-reliable serial attached SCSI disk drives can be used for mission critical and performance-oriented applications • High-capacity SATA drives can be used for disk enhanced backup or reference data

30 Performance & Capacity Tradeoffs

SAS systems deliver greater scalability in terms of IOPS & capacity per U

HDD Alternatives 15K 12 x 3.5” Drives in 2U Enclosure SAS/FC 147GB 10K 3U2U SAS/FC 300GB 7200 Performance Performance SATA 500GB Queued IOPS Per U Capacity 0 500 1000 1500 2000 2500

15K RPM SCSI SAS/FC SAS or Fibre 10K RPM Storage SAS/FC System 7200 RPM SATA ATA

0 1000 2000 3000 4000

GB Per U 31 SAS Delivers Scalable Throughput

Bandwidth Aggregation with Wide Ports

Up to 24 Gbps of bandwidth with 4 SAS 20,000 RAID Board links configured as a 18,000 16,000 8KB SAS wide port with full Transfer SAS 14,000 Interface Chips duplex communications 8KB FCAL 12,000 Transfer 10,000

IOPS 8,000 6,000 2Gbps FC SAS Expanders SAS Expanders 4,000 2,000 Arbitrated Loop 0 1 21 41 61 81 101 121 SAS SATA Number of Disk Drives Drive Drive FCAL - 8KB Transfers SAS - 8KB Transfers SAS SATA Drive Drive

• Four link, SAS controller provides scalable back-end bandwidth for up to 24Gbps data transfers with full duplex communications • Point-To-Point connections eliminate the shared media bottleneck ¾ Bandwidth aggregated over multiple, low-cost Serial Attached SCSI links ¾ Rate matching supports 1.5Gbs SATA and 3.0Gbs SAS drives for optimal performance 32 Fault Isolation

Serial Attached SCSI Provides Superior Fault Isolation

• FCAL Fault Isolation FCAL RAID Controller ¾ FCAL re-clocks data through each device in FCAL FCAL loop without verification Drive 1 Drive 126 Data re- clocked ªUp to 127 devices could be FCAL FCAL at fault on each loop. Drive2 Drive 125 through each device ªDevice interoperability FCAL FCAL between manufacturers can Drive 3 Drive 124 be a significant problem ¾ If problems arise, each device must be switched out of loop to isolate the RAID Board fault SAS RAID Controller No More ªIsolating more than one Than Three problem device can be difficult Edge Expanders Levels of Expanders • Serial Attached SCSI Fault are allowed Fan-out Expanders Isolation ¾ Point-To-Point connections Edge Expanders significantly enhance fault isolation SAS SAS Drive 1 Drive 125 ¾ No more than three layers of expanders are allowed SAS SAS Drive 2 Drive 126 33 Lower TCO Through Standardization

Dual port SAS SAS controller • Customers can lower their drives support communicates Total Cost of Ownership redundant RAID with SAS and controllers SATA drives (TCO) by standardizing on one platform for all of their external storage needs • IT managers can configure systems with SATA drives for Mid-line & Near-line applications • Or, configure the system to support online by High performance & high availability adding SAS drives and a SAS drives Connector second RAID controller. supports SAS & SATA Disks • SAS flexibility reduces the customer’s cost of

ownership High capacity & Lower cost SATA drives

34 Software Compatibility

• SAS employs the SCSI command set to maintain compatibility with installed base of operating systems and applications – SCSI command set is robust and stable • 20 years of investment and enhancements • Extensive IT management experience

• Support for the SCSI command set means only the underlying hardware changes – SAS will deliver more scalability and flexibility with existing applications

35 Interoperability & Multi-sourcing

• SAS was designed to be a disk interface and near cabinet connection technology only • This was established to keep costs low and improve vendor interoperability • SAS is an industry standard spec that defines device operation through extensive use of state diagrams • All major enterprise drive manufacturers are participating in the specification’s development • All enterprise drive manufacturers are expected to introduce disks with a SAS interface

36 Migration to Modular Designs

• Storage systems are migrating to a modular design approach – Pay as you grow • Enables selection of the optimal protocol for SAN attachment and disk connections – SAS offers redundancy and performance features of fibre channel with flexibility and cost structure to support SATA HDDs

SAN or Host Attachment FC or iSCSI

FC or iSCSI FC or iSCSI SAN Attachment SAN Attachment

Cache Cache

RAID RAID Insert iSCSI, or FC RAID

controller based on Disk Connections SAS customer requirements Disks Disk Connections

Disk Connections SATA Disks Disk Connections 37 Creating Graded Pools of Storage

Serial storage enables IT managers to create “graded pools of storage” to meet a broad range of application requirements within a common infrastructure

Dual port 10K or 15K rpm SAS drives for main stream server SAN applications

SATA drives for nearline storage Data Data Data

SATA drives for SAS or SATA HDDs disk enhanced Common Pool of Storage backup and restore processes

38 Summary and Q&A

• Today’s storage systems require the scalability and flexibility to support both online and nearline requirements driven by new regulatory requirements • Serial ATA and Serial Attached SCSI are new disk technologies that enhance storage flexibility, performance, and scalability • The first SAS storage systems will be introduced during the first of 2005

• Questions?

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