An Intelligent Storage Platform Architecture · Development considerations ... • Startups can’t...

© 2006 LSI Logic Corporation

An Intelligent Storage Platform ArchitectureUniversity of MinnesotaIntelligent Storage WorkshopMay 9, 2006

Jerry FredinDistinguished EngineerLSI Logic CorporationEngenio Storage Group

May 9, 2006 LSI Logic Corporation - Engenio Storage Group 2

Outline

• Issues with placement of intelligence in the IO path• Current solutions• Emerging solution• Potential applications• Architectural variations• Issues to investigate• Conclusion


Intelligence in the IO PathTechnical guidelines

• Resource UtilizationWhich buses and components in the IO path are usedWhat location minimizes utilization

• Device Span of ControlHow many devices are controlled by the intelligent componentThe higher in the IO path, the greater the span of controlTry to maximize number of devicesEases management

• Host AccessibilityAll hosts requiring access have a path to the intelligent elementReduces complexity of coordination between elements


SwitchSwitch

Intelligence in the IO Path

SwitchSwitchSwitchesSwitches

Filesystem

Volume Manager

SAN Switch

Storage Device

Device Driver

Storage Controller

SAN Appliance

StorageStorageSystemSystem

DiskDisk DiskDisk DiskDisk






Intelligence in the IO PathDevelopment considerations

• There are technical guidelines for proper placement

• But choices are often made for non-technical reasons

• Often because of development considerationsExpertise available

Minimize schedule risk

Maintain stability

Reduce testing


SwitchSwitch

Intelligence in the IO Path

SwitchSwitchSwitchesSwitches

Filesystem

Volume Manager

SAN Switch

Storage Device

Device Driver

Storage Controller

SAN Appliance








Placing Intelligence in the IO PathGoals and obstacles

• Want to integrate additional intelligence into the storage controller

• Partners want to leverage existing designs to minimize costs and risks

• Want to isolate new intelligence from existing code

• Established vendors can’t always revamp easilyHardware/Software architecture not conducive to adding all functions

• Startups can’t implement existing functionality High cost to re-invent current technology


• Partnering-friendly architecture

• Support broad range of intelligent functionsData management

Storage management

In band

Out of band

• Provide isolation of functionalityEnable parallel development

Reduce test effort and risk

• Keep costs in line with added value

What is needed


• ExamplesNAS

CAS

OSD

Isolates functionality

Minimizes risk

Broad range of functions

Costs

Complete system

Packaging

Interconnect

Rack space

Control Head

Current SolutionsControl Head

Storage Controller

Interconnect

Drive Interface

SAN/LAN


• Add an independent processor

• Isolates functionality

• Minimizes software risk

• Increases hardware complexity

• CostsAdditional memory

Additional processor chipset

Inter-processor communications

Current SolutionsDual Processors

Storage Controller

SAN/LAN

Drive Interfaces

IPC

Front-endProcessor/Memory

Complex

Back-endProcessor/Memory

Complex

XOR Host IF

Drive IFCache


• Add CPU in a SMP configuration

• Requires MPised software

• Increases software risk

• Can’t isolate software functions

• CostsAdditional CPU

Current SolutionsDual Processor SMP Configuration

Storage Controller

SAN/LAN

Drive Interface

Front-endProcessor

Back-endProcessor

XOR Host IF

Drive IFCacheNorthBridge

SharedMemory


• Single Socket Dual Core Processor

• SMP Configuration

• More cost effective than SMP CPUs

• Same software issues as SMP CPUs

Current SolutionsDual Core SMP Configuration

Storage Controller

SAN/LAN

Drive Interface

Shared Memory

Front-endCore

Back-endCore

XOR Host IF

Drive IFCache


Emerging Solution

• Dual core embedded processors• Independent (non-SMP) configuration

Shared physical memoryLogical memory ownership model

• Integrated DRAM controller• Integrated XOR engine• Integrated IO buses


• Dual Core Processor

• Independent Configuration

• Isolates functionality

• Minimizes software risk

• Reduced hardware complexity

• Costs

• Dual core vs. single core

Emerging SolutionDual Core Independent Configuration

Storage Controller

SAN/LAN

Drive Interface

Front-endCore

Back-endCore

XOR

Host IF

Drive IF

SharedMemory


Control Head

Architectural Progression

Storage Controller

Interconnect

Drive Interface

Drive Interfaces

IPC

Front-endProcessor/Memory

Complex

Back-endProcessor/Memory

Complex

XOR Host IF

Drive IFCache

Drive Interface

Front-endCore

Back-endCore

XOR

Host IF

Drive IF

SharedMemory


Architectural Case 1 Hosting a Data Management Application

Linux/BSD

IO request

Disk

Physically Shared Physically Shared MemoryMemory

Logically PartitionedLogically Partitioned

IPC

Coupling Driver

File System

Host IF Driver

Data Management Application

CouplingDriver

Basic RTOS Services

RAID

IO Interfaces CacheManager

Core #1

Core #2


Architectural Case 2 Hosting a Target Interface

IO request

Disk



IPCKernel Services

Coupling Driver

SCSIMid-Layer

Target Driver Coupling

Driver

Basic RTOS Services

RAID

IO Interfaces CacheManagerCore #1

Core #2


Architectural Case 3Hosting a Storage Management Application

Linux/BSD

IO request

Disk



IPC

Coupling Driver

File System

Mgmt IF Driver

Storage Management Application

CouplingDriver

Basic RTOS Services

RAID


Core #1

Core #2

Managementrequest


Architectural Case 4 Hybrid Application

Linux/BSD

IO request

Disk



IPC

Coupling Driver

File System

IF Drivers

Storage and Data Management Applications

CouplingDriver

Basic RTOS Services

RAID


Core #1

Core #2

Managementrequest

IO request


Architectural Cases

1. Hosting of a Data Management Application• User space, in-band, Linux application• Example: virtualizers, security, NAS, CAS, etc.

2. Hosting of a Linux target driver• Linux host device driver coupled to the second core• Example: iSCSI or Infiniband

3. Hosting of a Storage Management Application• Out-of-band administrative application• Example: Web-servers, CIMOM & providers, Mgt. tools

4. Hybrid Application• Combine selected features/functions of 1-3 above


Potential Applications

• Higher level applications in the data flowNAS (Networked Attach Storage)

OSD (Object Storage Device)

CAS (Content Addressable Storage)

Virtual Tape

• Block level data management applications in the data flow“Virtualizers” or in-band volume managers

Replication and copy services suites

Grid or storage clustering intelligence

Security applications

• Storage Management and administrative applicationsWeb-servers for browser support

CIMOM & SMI-S providers

Hosting diagnostic or performance tools


Areas to investigate

• Performance levels• Impact to existing code• Optimizations to coupling between cores• Applicability of standard hardware platform to broad

list of features• Can one software infrastructure support the list of

potential features


Conclusions

• Emerging independent cores have potential for:Functional isolationMinimized impact to existing functionalityGood cost/value

• Still issues to resolveShared memory impact on existing functionalityPerformance requirements vs. capabilityInfrastructure acceptance

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