Measuring Interface Latencies for SAS, Fibre Channel and iscsi

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Measuring Interface Latencies for

SAS, Fibre Channel and iSCSI

Dennis Martin

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Demartek Company Overview

 Industry analysis with on-site test lab

 Lab includes servers, networking and storage

infrastructure

 Fibre Channel: 4 & 8 Gbps (16Gb soon)

 Ethernet: 1 & 10 Gbps (including NFS, CIFS, iSCSI & FCoE)

 Servers: 8+ cores, very large RAM

 Virtualization: ESX, Hyper-V, Xen

 We prefer to run real-world applications to test servers

and storage solutions

 Currently testing various SSD and FCoE implementations

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Demartek News

 Demartek Deployment Guides

 Completed: iSCSI – May 31, 2011

 In-progress: SAS, SSD & 16Gb Fibre Channel

 Free Monthly Newsletter



http://www.demartek.com/Newsletter/Newsletter_main.html

 Text “DemartekLabNotes” to 22828

 Storage Interface Comparison

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Latency is Important

 OLTP applications require short response

times (small latencies)

 Some transactions require several successive

queries in order to provide complete response

 HDDs have same maximum RPM (15000) as

a decade ago, limiting latency improvements

 RAID5 striping and latency

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Host Storage Interfaces

 The host storage system interface matters

 We compared the performance and latency of

the same storage system with multiple host

interfaces

 What kinds of performance and latency would

you expect from these four host interfaces?

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Performance – Random IOPS

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000

4KB rnd read 8KB rnd read 16KB rnd read 32KB rnd read 64KB rnd read 4KB rnd write 8KB rnd write 16KB rnd write32KB rnd write64KB rnd write

SQLIO - IOPS (Random)

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Performance – Random MBPS

0 200 400 600 800 1000 1200

4KB rnd read 8KB rnd read 16KB rnd read 32KB rnd read 64KB rnd read 4KB rnd write 8KB rnd write 16KB rnd write 32KB rnd write 64KB rnd write

SQLIO - MBPS (Random)

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Performance – Sequential IOPS

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 4KB seq read 8KB seq read 16KB seq read 32KB seq read 64KB seq read 128KB seq read 256KB seq read 4KB seq write 8KB seq write 16KB seq write 32KB seq write 64KB seq write 128KB seq write 256KB seq write

SQLIO - IOPS (Sequential)

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Performance – Sequential MBPS

0 200 400 600 800 1000 1200 1400 4KB seq read 8KB seq read 16KB seq read 32KB seq read 64KB seq read 128KB seq read 256KB seq read 4KB seq write 8KB seq write 16KB seq write 32KB seq write 64KB seq write 128KB seq write 256KB seq write