introduction to storage

Introduction To StorageIntroduction To Storage

Overview of the storage Overview of the storage subsystemsubsystem

Objectives for this UnitObjectives for this Unit Understand Storage BasicsUnderstand Storage Basics Introduce Direct Attached StorageIntroduce Direct Attached Storage Differentiate between types of Differentiate between types of

storagestorage DASDAS NASNAS ISCSIISCSI SANSAN

Introduce Network Attached StorageIntroduce Network Attached Storage Introduce Fibre Channel SANIntroduce Fibre Channel SAN

A Few Storage Basics….A Few Storage Basics…. Where will data finally end up? Where will data finally end up? How will it get there?How will it get there? What will it pass through?What will it pass through?

Direct Attached Storage Direct Attached Storage (Internal)(Internal)

Computer System

CPU

Memory

Bus

I/O - RAID Controller

Disk Drives


Computer System

CPU

Memory

Bus


Disk Drives

12345

John Smith512-555-1212

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Data


Computer System

CPU

Memory

Bus


Disk Drives

12345


1424 Main Street

DAS w/ internal controller DAS w/ internal controller and external storageand external storage

CPU

Memory

Bus


Computer System

Disk Drives

Disk Drives

Disk Drives

Disk Enclosure

12345


1424 Main Street

Comparing Internal and Comparing Internal and External StorageExternal Storage

Internal Storage

Server

Storage

RAID controllers and disk drives are internal to the server

SCSI, ATA, or SATA protocol between controller and disks

SCSI Bus w/ external storage

Server

RAID Controller

Storage

RAID Controller

Disk Drives

RAID controller is internal

SCSI or SATA protocol between controller and disks

Disk drives are external

Disk Drives

DAS w/ external controller DAS w/ external controller and external storageand external storage

Computer System

CPU

Memory

Bus

HBA

RAIDController

Storage System

Disk Drives

Disk Drives

Disk Drives

Disk Enclosure12345


1424 Main Street

DAS over Fibre ChannelDAS over Fibre ChannelServer

HBA

Storage

Disk drives and

RAID controller are external

Disk Drives

RAID Controller

HBA is internal

Fibre Channel protocol between HBAs and external RAID controller

External SAN Array

I/O TransferI/O Transfer RAID ControllerRAID Controller

Contains the “smarts”Contains the “smarts” Determines how the data will be written Determines how the data will be written

(striping, mirroring, RAID 10, RAID 5, etc.)(striping, mirroring, RAID 10, RAID 5, etc.)

Host Bus Adapter (HBA)Host Bus Adapter (HBA) Simply transfers the data to the RAID Simply transfers the data to the RAID

controller. controller. Doesn’t do any RAID or striping calculations. Doesn’t do any RAID or striping calculations. ““Dumb” for speed.Dumb” for speed. Required for external storage.Required for external storage.

Storage typesStorage types Single Disk DriveSingle Disk Drive JBODJBOD VolumeVolume Storage ArrayStorage Array SCSI deviceSCSI device DAS DAS NASNAS SANSAN iSCSIiSCSI

NAS: What is it?NAS: What is it?

Network Attached StorageNetwork Attached Storage Utilizes a TCP/IP network to “share” Utilizes a TCP/IP network to “share”

datadata Uses file sharing protocols like Unix Uses file sharing protocols like Unix

NFS and Windows CIFSNFS and Windows CIFS Storage “Appliances” utilize a Storage “Appliances” utilize a

stripped-down OS that optimizes file stripped-down OS that optimizes file protocol performanceprotocol performance

Networked Attached Networked Attached StorageStorage

NAS Server

Storage

Server has a Network Interface Card

No RAID Controller or HBA in the server

Public or Private Ethernet network

RAID Controller

Disk Drives

All data converted to file protocol for transmission (may slow down database transactions)

Server

NIC NIC

iSCSI: What is it?iSCSI: What is it?

An alternate form of networked storageAn alternate form of networked storage Like NAS, also utilizes a TCP/IP networkLike NAS, also utilizes a TCP/IP network Encapsulates native SCSI commands in Encapsulates native SCSI commands in

TCP/IP packetsTCP/IP packets Supported in Windows 2003 Server and Supported in Windows 2003 Server and

LinuxLinux TCP/IP Offload Engines (TOEs) on NICs TCP/IP Offload Engines (TOEs) on NICs

speed up packet encapsulationspeed up packet encapsulation

iSCSI StorageiSCSI Storage

iSCSI Storage

Server has a Network Interface Card or iSCSI HBA

iSCSI HBAs use TCP/IP Offload Engine (TOE)

Public or Private Ethernet network

RAID Controller

Disk Drives

SCSI commands are encapsulated in TCP/IP packets

Server

NIC or iSCSI HBA NIC or iSCSI HBA

Fibre Channel: What is it?Fibre Channel: What is it?

Fibre Channel is a network protocol Fibre Channel is a network protocol implemented specifically for implemented specifically for dedicated storage networksdedicated storage networks

Fibre Channel utilizes specializedFibre Channel utilizes specialized SwitchesSwitches Host Bus AdaptersHost Bus Adapters RAID controllersRAID controllers CablesCables

switch

Fibre Channel Fibre Channel ComponentsComponents

RAID Controller RAID Controller

switch

ServersServers Host Bus AdaptersHost Bus Adapters

CablesCables Fiber optic or copperFiber optic or copper

Fibre Channel SwitchesFibre Channel Switches Two switches for Two switches for

redundancyredundancy Fibre Channel Storage Fibre Channel Storage

ArrayArray Two RAID Controllers for Two RAID Controllers for

redundancyredundancy 4–100+ disk drives per 4–100+ disk drives per

arrayarray A true storage networkA true storage network

Multiple serversMultiple servers Multiple switchesMultiple switches Multiple Storage ArraysMultiple Storage Arrays

Server A

HBA

Server B

HBA

Server C

HBA

Disk Drives

FC Storage Array

HBA HBA HBA

SAN: What is it?SAN: What is it?

Storage Area NetworkStorage Area Network A network whose primary purpose is the A network whose primary purpose is the

transfer of data between storage systems transfer of data between storage systems and computer systemsand computer systems

Fibre Channel is the primary technology Fibre Channel is the primary technology utilized for SANsutilized for SANs

Recently, SANs have been implemented Recently, SANs have been implemented with dedicated iSCSI networkswith dedicated iSCSI networks

Benefits of SAN/Consolidated Benefits of SAN/Consolidated StorageStorage Reduce cost of external storageReduce cost of external storage Increase performanceIncrease performance Centralized and improved tape Centralized and improved tape

backupbackup LAN-less backupLAN-less backup High-speed, no single-point-of-High-speed, no single-point-of-

failure clustering solutions failure clustering solutions Consolidation with > 70TB of Consolidation with > 70TB of

storage storage

Fibre Channel TechnologyFibre Channel Technology Provides concurrent communications between Provides concurrent communications between

servers, storage devices, and other peripheralsservers, storage devices, and other peripherals A gigabit interconnect technologyA gigabit interconnect technology FC1: Over 1,000,000,000 bits per secondFC1: Over 1,000,000,000 bits per second FC2: Over 2,000,000,000 bits per secondFC2: Over 2,000,000,000 bits per second A highly reliable interconnectA highly reliable interconnect Up to 127 devices (SCSI: 15)Up to 127 devices (SCSI: 15) Up to 10 km of cabling (3-15 ft. for SCSI)Up to 10 km of cabling (3-15 ft. for SCSI) Physical interconnect can be copper or fiber opticPhysical interconnect can be copper or fiber optic

Fibre Channel – Fibre Channel – (continued)(continued) Hot-pluggable - Devices can be Hot-pluggable - Devices can be

removed or added at will with no ill removed or added at will with no ill effects to data communicationseffects to data communications

Provides a data link layer above the Provides a data link layer above the physical interconnect, analogous to physical interconnect, analogous to EthernetEthernet

Sophisticated error detection at the Sophisticated error detection at the frame levelframe level

Data is checked and resent if Data is checked and resent if necessarynecessary

Fibre Channel – Frame Fibre Channel – Frame DissectionDissection

Up to 2048 byte Up to 2048 byte payloadpayload

4 byte 4 byte checksum for checksum for each frameeach frame

Fibre ChannelFibre Channel

What’s with the funny name?What’s with the funny name? Some background history requiredSome background history required Originally developed to only support Originally developed to only support

fiber optic cablingfiber optic cabling When copper cabling support was When copper cabling support was

added, ISO decided not to rename the added, ISO decided not to rename the technologytechnology

ISO changed to the French spelling to ISO changed to the French spelling to reduce association with fiber optics only reduce association with fiber optics only mediummedium

Fibre ChannelFibre Channel

How does it work?How does it work? Serial interfaceSerial interface Data is transferred across a single piece Data is transferred across a single piece

of medium at the fastest speed of medium at the fastest speed supportedsupported

No complex signaling requiredNo complex signaling required

Fibre Channel Interface Fibre Channel Interface LayersLayers

Device Driver

SCSI Protocol

Fibre Channel

Fiber Optic or Copper Cabling

SCSI vs. Fibre ChannelSCSI vs. Fibre ChannelProtocolProtocol SCSISCSI

SCSI protocol vs. SCSI deviceSCSI protocol vs. SCSI device SCSI is an established, tried and true protocolSCSI is an established, tried and true protocol Provides services analogous to TCP/IPProvides services analogous to TCP/IP Supported in every major OS on marketSupported in every major OS on market

Fibre ChannelFibre Channel Fibre Channel runs on top of SCSIFibre Channel runs on top of SCSI No re-inventing the wheelNo re-inventing the wheel Immediate OS supportImmediate OS support

SCSI vs. FC TransmissionSCSI vs. FC Transmission

RAID Controller Disk Drive

Fibre Channel

SCSI

RAID Controller Disk Drive

SCSI SCSI vs. vs. Fibre Fibre ChannelChannel

Interface for internal storage Interface for internal storage to external disksto external disks

Potential down time w/ SCSIPotential down time w/ SCSI Single busSingle bus RAID controller is SCSI RAID controller is SCSI

hardwarehardware Standards: Standards:

Ultra2 (80 MB/sec) Ultra2 (80 MB/sec) Ultra 160 (160 MB/sec)Ultra 160 (160 MB/sec) Ultra 320 (320 MB/sec)Ultra 320 (320 MB/sec)

Media specific (copper only)Media specific (copper only) SCSI Limitations:SCSI Limitations:

Cables can’t be any Cables can’t be any longer than 3 feet for longer than 3 feet for single ended; 15 feet for single ended; 15 feet for LVD (low voltage LVD (low voltage differential)differential)

No more than 15 devices No more than 15 devices on a SCSI buson a SCSI bus

# of disk drives# of disk drives

Used with SANUsed with SAN Lots of built-in redundancy with Lots of built-in redundancy with

connectionsconnections Redundant networkRedundant network HBA is fibre channel hardwareHBA is fibre channel hardware Standards: Standards:

FC1: 100 MB/secFC1: 100 MB/sec FC2: 200 MB/secFC2: 200 MB/sec

Provides a data link layer above the Provides a data link layer above the physical interconnectphysical interconnect Analogous to EthernetAnalogous to Ethernet FC is a network of devicesFC is a network of devices It can be media independent- copper It can be media independent- copper

or fibre opticor fibre optic Fibre Channel limitations:Fibre Channel limitations:

Cable length: Up to 10 kilometers Cable length: Up to 10 kilometers (more a limitation of cable than FC (more a limitation of cable than FC itself)itself)

Up to 127 devicesUp to 127 devices # of disk drives# of disk drives

Fibre Channel vs. iSCSIFibre Channel vs. iSCSI Fibre ChannelFibre Channel

The current market leader for shared storage The current market leader for shared storage technologiestechnologies

Provides the highest performance levelsProvides the highest performance levels Designed for mission-critical applicationsDesigned for mission-critical applications Cost of components is relatively high, particularly per Cost of components is relatively high, particularly per

server HBA costsserver HBA costs Relatively difficult to implement and manageRelatively difficult to implement and manage

iSCSIiSCSI Relatively new, but usage is increasing rapidlyRelatively new, but usage is increasing rapidly Performance can approach Fibre Channel speedsPerformance can approach Fibre Channel speeds A better fit for databases than NASA better fit for databases than NAS A good fit for Small to Medium Size BusinessesA good fit for Small to Medium Size Businesses Relatively inexpensive, compared to Fibre ChannelRelatively inexpensive, compared to Fibre Channel Relatively easy to implement and manageRelatively easy to implement and manage

Microsoft Simple SAN Microsoft Simple SAN InitiativeInitiative Make operating system aware of SAN and SAN Make operating system aware of SAN and SAN

capabilitiescapabilities Shift integration burden from IT staff or services Shift integration burden from IT staff or services

back to VENDORS products:back to VENDORS products: MicrosoftMicrosoft Storage hardware and softwareStorage hardware and software Application developersApplication developers

Key storage technologies:Key storage technologies: Volume Shadow Copy Service (VSS)Volume Shadow Copy Service (VSS) Virtual Disk Service (VDS)Virtual Disk Service (VDS) Microsoft Multipath Input/Output (MPIO)Microsoft Multipath Input/Output (MPIO) Microsoft iSCSI driverMicrosoft iSCSI driver

Software Initiator (client)Software Initiator (client) Software Target (attached to disk subsystem)Software Target (attached to disk subsystem)

ReviewReview What is the difference between a RAID What is the difference between a RAID

Controller and an HBA?Controller and an HBA? How many protocols may be used for How many protocols may be used for

DAS?DAS? Name two types of storage that rely on Name two types of storage that rely on

ethernet cablesethernet cables Name two benefits of SANsName two benefits of SANs Describe the four interface layers of the Describe the four interface layers of the

Fibre Channel protocolFibre Channel protocol Describe a scenario where an iSCSI SAN Describe a scenario where an iSCSI SAN

may be preferred over a Fibre Channel may be preferred over a Fibre Channel SANSAN

SummarySummary How data is routed through a server to I/OHow data is routed through a server to I/O Types of storageTypes of storage

DASDAS NASNAS iSCSIiSCSI SANSAN

Benefits of SAN technologyBenefits of SAN technology Storage consolidationStorage consolidation Reduced costsReduced costs Centralized, LAN-free backup and restoreCentralized, LAN-free backup and restore

The Fibre Channel protocolThe Fibre Channel protocol How it worksHow it works Fibre Channel protocol vs. SCSI protocolFibre Channel protocol vs. SCSI protocol

Comparing Fibre Channel SANs and iSCSI SANsComparing Fibre Channel SANs and iSCSI SANs Fibre Channel SANs offer mission-critical performance, with relatively Fibre Channel SANs offer mission-critical performance, with relatively

high costs and high complexityhigh costs and high complexity iSCSI SANs offer moderate to high performance at an attractive iSCSI SANs offer moderate to high performance at an attractive

price/performance ration and are relatively easy to administerprice/performance ration and are relatively easy to administer

introduction to storage

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