Information Lifecycle Management – Presented By MCSI Technology Trends ATA Disk.

Information Lifecycle Management – Presented By MCSI

Technology Trends

ATA Disk


Agenda

• ATA Disk– Overview– Parallel vs Serial– Phases of Serial ATA– SCSI vs SATA– Uses


ATA Disk Overview

• Advanced Technology Attachment (ATA)– Remember when ‘AT’ was the advance from ‘XT’?

• Used primarily in Desktop systems• Millions produced and in use today• Parallel ATA (PATA) most prevalent

– Also known as Ultra-ATA– w/in ‘enterprise’ market, made up between 5-10%

in 2002 – predicted to double in 2003• Serial ATA (SATA) clearly improved and will replace

Parallel in the near future– Has a 10-year roadmap– Will challenge SCSI– Parallel continues thru 2005


Parallel ATA vs Serial ATA

Comparison PATA SATA SATA Advantage

Transfer Rate 3MBs – 133MBs 150MBs – 600MBs

6x Performance enhances productivity

Voltage 5 Volt 250mV Less Power, less heat, good for mobile use

Cable & Connector

18in, 80-conductor, 40-pin flat ribbon

<1m, thin & flexible 4 signal

pins

Easier cable routing, improved ventilation, higher reliability (skew), greater scalability

Hot Plug No standard defined

Supported w/defined standard

Increased up-time & availability (in a way, better than FC b/c of loop insert issues)

Connectivity Shared

(Master/Slave)

Point-to-Point Eliminates confusion, improved performance

Computer Technology Review, July 2003, Pg36


The Serial ATA Types & Phases

• SATA 1– Shipping Today, 150MBs

• SATA 2 Phase 1– 150MBs– Support backplane connectivity, enclosure

monitoring (heat, etc), command tag queuing• SATA 2 Phase 2

– 300MBs– Dual-porting for active-active controllers,

Command Tag Queuing (CTQ)– Often referred to as SATA II – a misnomer


The Serial ATA Types & Phases

• Serial SCSI (SAS)– Has been around but there has been little need

because of FC drives– SAS can share the same controller as SATA– Provides ability to accommodate different

performance and reliability requirements into a common architecture


SCSI vs ATAPerformance & Reliability Criteria Comparison

ATA SCSI SCSI/ATA

RPM 7,200 15,000 208%

Test Cache on Drive (MB) 8 8 100%

HDTach Sequential Read (avg MB/s) 45.5 64.7 142%

HDTach Sequential Write (avg MB/s) 27.7 42.6 154%

HDTach Random Access Time (ms) 13 5.7 44%

IOMeter Desktop IOPS 150 360 240%

IOMeter Desktop avg response time (ms) 424 177 42%

IOMeter Web Server IOPS 143 408 285%

IOMeter Web Server avg response time (ms) 6.18 2.508 41%

MTBF (thousands of hours) 600 1200 200%

Duty cycle (hours per day) 8 24 300%

Storage Magazine, October 2003, Pg 22



• ‘Enterprise Class’ disks have– Better thermodynamics– Stiffer, lighter & more resilient actuators– Longer testing cycles– Deeper command tag queuing

• than their ‘Desktop Class’ brethren

however, the line blurrs….

• Western Digital Raptor SATA Disk– 36GB, 10K rpm, 5.2ms Seek– 1.2 million hour MTBF– 30% cheaper than SCSI disk



• With regard to reliability– What everyone is really after is not disk reliability

but application availability (EMC mantra forever)• To achieve it using SATA, we have:

– RAID, Hot-Swap-ability, Hot-Sparing, Redundant Components

• With regard to performance– What percentage of your Servers have IOPS or

throughput requirements approaching SCSI or FC capacities?

• In most environments, this percentage is low and for the servers that need it, FC or SCSI is available

• For the majority, SATA will meet application performance requirements.


Uses for ATA Disk

• Backup to Disk– Not an automatic fix for backup problems

• Need to find the bottleneck first– If it is tape, then it can help right away

– Helps if quick restore is the requirement– Approaches

• Virtual Tape Libraries (VTL)• D2D• Integrated Disk/Tape subsystems (ADIC)


Uses for ATA Disk

• Information Lifecycle Management– Value of data changes over time– ATA-based subsystems provide a cost

effective medium between high performance disk and tape

• Departmental or low activity servers & applications• Target for HSM software• Target for ‘Reference Data’

– Everyone’s jumping on the ILM bandwagon• STK has Trademarked “ILM”


Uses for ATA Disk

• Disaster Recovery– Inexpensive Target for Data Replication to

a remote site• Primary disk is high-performance, highly

functional disk• Target disk is ATA Disk Subsystem

– Use Host-Based replication Technologies• EMC RepliStor or NSI DoubleTake

– Some ATA-Based arrays have array-array replication software built-in

• EqualLogic PeerStorage


ATA Resources

• http://www.serialata.org• http://www.sata-io.org

Information Lifecycle Management – Presented By MCSI Technology Trends ATA Disk.

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