storage basics

11

Storage Basics

22

Agenda/learning objectives

Introduce the components of the computer and show how they request and store data

Introduce RAID technology and RAID protection schema

Introduce Storage Area Networks and Network Attached Storage

Introduce different data protection capabilities available

Show how all the components fit into the Information Lifecycle Management vision

33

The Input / Output Machine

The CPU or Central Processing Unit(Server)

The CPU or Central Processing Unit(Server)

INP

UT

“Print thisE-mail”

OU

TP

UT

INP

UT

“OpenForecast.doc”

OU

TP

UT

INP

UT

“Save changesto Forecast.doc”

OU

TP

UT

44

Where Data Is Stored

Main MemoryMain Memory

Very fast access—no moving parts Very expensive compared to mechanical or magnetic storage Volatile—represents “one’s” and “zero’s” with positive or negative

charge of electricity - data is lost if there is no source of power Provides instructions and data to the CPU and stores results of

CPU calculations—information constantly changing during processing

55

Where Data is Stored

Non-Volatile Magnetic Memory: Tape and DiskNon-Volatile Magnetic Memory: Tape and Disk

Storage surface coated with magnetic substance Ones and zeros represented by positive or negative magnetic

polarization Retains magnetic polarization even without power Mechanical operation to position a read / write head, over a specific

area of the magnetic surface to:– Write data: write head changes the magnetic pole to positive or negative to

represent a one or zero– Read data: read head senses the positive or negative pole that represents a

one or zero

66

First Magnetic Tape Drive - 1952

77


TapeTape

Organizes data sequentially on the tape in the order it receives the information

More general and simplistic formatting—allows tapes written by one system to be read to a different system in many cases

Cannot directly access each piece of data—it reads from the beginning of the tape until it gets to the data requested

Sequential Access provides good performance to read or write large amounts of data from start to finish, but very poor performance for random access

The tape is independent from the tape drive making it easily portable to other systems or to a safe location

88

First Magnetic Storage Devices for Computers

99

First Magnetic Storage Devices for Computers

1010


DiskDisk

Organizes data into specific and addressable areas to read or write data directly

The disk must be formatted to match the disk addressing structure of the operating system

Direct access provides fairly consistent performance for mixed tasks of reading and writing sequential and random groups of data

Disk performance can be impacted by the length of idle time necessary to position the read / write head over the area being addressed

Disk is physically connected to the system—impractical or impossible to move the disk to a new location or new system

1111

System Bus

CPUCPU

MAIN MEMORYMAIN MEMORY(RAM)(RAM)

ROMROM(Read Only Memory)(Read Only Memory)

HB

AH

BA

Physical Disk Connections

Rules for physical connection– Type of cable– Number of paths– Physical connectors

Rules for logical connection– To identify a read or write command vs. data

Format of drive– Addressing scheme

Controller system or circuit card

– ESCON for mainframe

– Host bus adapters for open systems– Proprietary cards for AS/400

1212

System Bus

CPUCPU



HB

AH

BA

How the I/O Works

Initiating the Read Request

1313

System Bus

CPUCPU



HB

AH

BA

How the I/O Works

Completing the Read Request

1414

System Bus

CPUCPU

MAINMAINMEMORYMEMORY

(RAM)(RAM)


HB

AH

BA

A Smarter Way to Use Main Memory and CPU

Customer 1 Meter Reading



Customer 1Meter Reading


“Let’s see, customer 1, then customer 2, what might be next? ... I predict customer 3”

CA

CH

E


1515








System Bus

CPUCPU



HB

AH

BA

CPUCPU

CA

CH

E

1616

System Bus

CPUCPU



How the I/O Works

HB

AH

BA

Initiating the Write Command

1717

System Bus

CPUCPU



How the I/O Works

HB

AH

BA

Completing the Write Command

1818




System Bus

CPUCPU




HB

AH

BA

CPUCPU

CA

CH

E

WRITE COMMAND“The Customer’s

Completed monthly Bill”The Write Confirmationis issued as soon as the data

and write command are securein a completely fault

tolerant area

The Write Confirmationis issued as soon as the data

and write command are securein a completely fault

tolerant area

1919

Peripheral Components of a Computer System

HB

AH

BA

HB

AH

BA

NICNIC

HB

AH

BA

System Bus

CPUCPU



Storage ArrayStorage Array Tape Drive DeviceTape Drive DeviceNetworkNetworkRouterRouter

SANSANSwitchSwitch

2020

Data Storage: A Closer Look

Disk Drive

Memory Board

Tape Cartridge

2121

The Disk Drive: A Closer Look

2222

Formatting the Drive for Direct Access

A uniquely addressable area within a A uniquely addressable area within a disk drive is Cylinder, Head, and Sectordisk drive is Cylinder, Head, and Sector

Track The Disk Platter is segmented into a number of concentric rings, called Tracks

Cylinder

A specific Track in the same position on all of the disk platters in a spindle, together is called a Cylinder

The disk platter is also segmented into individual wedge shaped sections called Sectors

Sector

2323

Disk Drive Access Time

Seek Time: Seek Time:

The average amount of time necessary to move the actuator arm to position the read / write head over the track

2424


Latency:Latency:

The average amount of time necessary to wait for the data to arrive to the read / write as the disk spins

Also called rotational delay

2525


Transfer Rate: Transfer Rate:

The amount of time necessary to read data from, or write data to, the platter and move the data through the disk drive.

2626

Disk Drive Performance Variables

Seek time speed RPM speed of the disk platters

– Faster RPM reduces latency– Faster RPM has minor impact on

transfer rate

Disk drive interface speed– Ultra SCSI 40 MB/sec– Fibre channel 100MB/sec

2727

Evolution of Disk Technology

Drive capacities continue to increase dramatically from increased data density

Performance increasing marginally– Increased RPM speed– Increased use of memory and cache at the drive level

Disk drive interfaces driven by industry standards– Ultra SCSI– Fibre Channel– ATA

Industry challenge– Higher capacity per disk drive reduces cost, but…– Reduces the number of actuators for a given capacity

2828

Symmetrix CLARiiON Centera

SAN / NAS

SAN / NAS /Backup-to-Disk CAS

Tape &Tape

Emulation

DMX800

DMX1000-M2

DMX1000

DMX2000-M2

DMX2000

DMX3000-M2

DMX3000

CX700

CX500

CX300

Centera

AX 100 Netwin 110

NS700/G

CelerraCNS

ADIC Scalar SeriesDL700

EMC Storage Offerings

2929

Inside the Disk Arrays

Fault TolerantCache Memory

Array Controller Array Controller

Disk Directors Disk Directors

Host Interface Host Interface

3030

RAID Technology

RedundantArrays ofIndependentDisks

3131

RAID 0: Striping Data Across Many Disks without Adding Redundancy

Volume 1End

Raid 0Defined to the host computer as above, but data is physically moved to balance activity

Volume 1Middle

Volume 1BeginningWithout RAID

3 physical drives Defined to the host computer Volume 2Volume 2

EndEnd

Volume 2Volume 2MiddleMiddle

Volume 2Volume 2BeginningBeginning

Volume 3Volume 3EndEnd



Volume 1End



Volume 1Middle



Volume 1Beginning



3232

RAID 1 or Mirroring

Without RAID3 physical drivesDefined to the host computer

RAID 1A mirrored pair is created for each physical volume

Volume 1End

Volume 1Middle

Volume 1Beginning







Volume 1End

Volume 1Middle

Volume 1Beginning

Volume 1End

Volume 1Middle

Volume 1Beginning













3333

RAID 0 + 1 Performance and Redundancy

RAID 1 + 0A mirrored pair is created for each physical volume Volume 1

EndVolume 2Volume 2

EndEndVolume 3Volume 3

EndEndVolume 1

EndVolume 2Volume 2

EndEndVolume 3Volume 3

EndEnd

Volume 1Middle



Volume 1Middle



Volume 1Beginning



Volume 1Beginning



Without RAID3 physical drivesDefined to the host computer Volume 1

End

Volume 1Middle

Volume 1Beginning







3434

Data Parity

Parity for 3rd

Group = 11 LOST DATALOST DATA11

Parity for 2ndParity for 2ndGroup = 1Group = 1 01100

Parity for 1Parity for 1stst

Group = 0Group = 00 11 11Group 1

Group 2

Group 3

Group 1 0 + 1 + 1 = 0

Group 2 0 + 1 + 0 = 1

Group 3 1 + 1 + ? = 1

DATA + DATA + DATA = Parity

3535

RAID 5

Parity for1st Group

Volume 1End



Parity for Parity for 2nd Group2nd Group

Volume 1Middle



Parity forParity for3rd Group3rd Group

Volume 1Beginning



Without RAID3 physical drivesDefined to the host computer Volume 1

End

Volume 1Middle

Volume 1Beginning







RAID 5A group of drives are bound together as a physical volume

3636

0 Striping with no Parity Large Block Performance, No Redundancy

1 Mirrored Disks Highest Availability and Performance Simple Implementation

2 Hamming Code Large Block PerformanceMultiple Check Disks Availability, Poor Cost

3 Striping with Parity Large Block PerformanceSingle Check Disk Availability at Less Cost

4 Independent Read/Write Transaction Processing, High Availability,Single Parity Disk High

Percentage of Reads

5 Independent Read/Write Transaction Processing, High Availability, Independent Parity Disks High

Percentage of Reads

6 Independent Read/Write Transaction Processing, High Availability, Multiple Independent Parity Disks High

Percentage of Reads

Raid Level Technique Application

RAID Levels

3737

Storage Consolidation

Server/storage islands due to distributed computing model

Difficult to manage with reduced manpower

Poor utilization of storage

Integration of infrastructure due to merger/acquisition is difficult

Asset management is difficult

Server/Storage environmentTypical customer challenges:

3838

What is a Storage Area Network (SAN)?

…A dedicated network carrying block-based storage traffic

Users / ApplicationClients

Servers / Applications Storage / ApplicationData

SANSwitchesDirectors

LANSwitches

IPNETWORK

Fibre ChannelNETWORK

3939

SAN Benefits

High availability and manageability– All servers access same storage– Simplified management– Service for multiple platforms

Application performance– SAN provides a dedicated network– DBMS / transaction processing– Fastest record access

Fast scalability– Hundreds of servers – Hundreds of storage devices– Leverages existing infrastructure– Overcomes distance limitations

Better replication and recovery options

Storage consolidation optimizes TCO

4040

What is Network Attach Storage (NAS)?

…A network carrying file-based traffic

Users / ApplicationClients

Servers / Applications Storage / File Data

SANSwitchesDirectors

LANSwitches

IPNETWORK

Fibre ChannelNETWORK

Gateway

4141

NAS Benefits

Global access to information– File sharing– Any distance– Many to one, or one to many– Access from multiple platforms

Consolidation minimizes TCO

Collaboration– Improve time to market– Improve product quality

Information management– Leverage existing security– Leverage existing personnel– Leverage existing infrastructure

Replication and recovery options

Scalable without server changes

4242

High Availability

Typical customer issues:

Mission critical data – requires 7x24 uptime– No single point of failure (SPOF)

Time to market requirements are tighter– Development cycle is shorter– Development of technology is quicker– Competition is everywhere

Amount of data is growing, backup windows are shrinking

Meet Recovery Point Objectives (RPO) and Recovery Time Objectives (RTO) easier

4343

Data Path Protection

4444

What is Path Management Software? Allows you to manage multiple paths to a device to maximize

application uptime– Path

• Refers to the route traveled by I/O between a host and a logical device. • Comprises a host bus adapter (HBA), one or more cables, a switch or hub, an

interface and port, and a logical device.– Multi-Pathing

• Configuring multiple paths to a single logical device

Redirect I/O– For Load Balancing– For Path Failover

Monitor– HBAs, Paths, and Devices

Manage– Priorities, Policies for information access– Reconfiguration– Component repair

4545

Path Management Overview

Mirrored CacheSP B

0 1 2 3 0 1 2 3

Server

HBA0

HBA1

Mirrored CacheSP A

0 1 2 30 1 2 3

4 Paths Configured– 2 from each HBA through

switch to each SP

Provides Data Access

Provides Failover – Upon HBA, switch or SP failure

Provides Potential for Load Balancing

Four native devices configured – c1t2d1, c1t2d2, c2t2d1 and

c2t2d2

4646

Local Replication Protection

4747

SnapShots: Logical Point-in-Time Views

Pointer-based copy of data– Takes only seconds to create a

complete snapshot– Requires only a fraction of original file

system

Snapshots can be persistent across re-initialization of the array

Can be used to restore Source data

Up to eight snapshots can be created per Source LUN

ProductionInformation

Snap

snapshot

Logical Point-In-Time View

snapshotsnapshot

snapshotsnapshot

snapshotsnapshot

snapshot

4848

SP Memory

OriginalBlock C

Snap Shot “Copy-on-First-Write”

Block A

Block B Reserved LUN

Secondary Host

Production Host

Block C in the Reserved LUN now reflects the change that the Production Application made and the pointer is updated to point to the Reserved LUN for Block C

Source LUN

0 0 0

0 0 00 000 0 0

0 00

00 0

00

UpdatedBlock C

Block D 1

Block A

Block B

Block C

Block D

4949

BCVs: Full Image Copies

ProductionInformation

Clone

BCV

Full Image Copies

BCVBCV

BCVBCV

BCVBCV

BCV

Physically independent point-in-time copies of source volume

– Available after initial synchronization– Once established, no performance impact

between source / BCV– Can be used to restore or replace source in

event of hardware or software error

Can be incrementally re-established – Only changed BCV data overwritten by source

Up to eight BCVs can be established against a single source LUN concurrently

– Can be any RAID type or drive type(regardless of source)

5050

Remote Replication Protection

5151

Remote Replication Business Drivers

Primary Applications– Disaster Recovery– Business Continuance

Secondary Applications– Backup– Testing– Data Warehousing/mining– Content Distribution– Report Generation

5252

Recovery Objectives Recovery Point Objective (RPO)

– How far back in time does data need to be recovered if disaster occurs ?

Recovery Time Objective (RTO)– How much time will pass after a disaster before operations

are online again?

5353

Replication Models

Synchronous

Asynchronous– Periodic incremental update– Traditional asynchronous– Semi-synchronous– Full copy

5454

Replication Model - Synchronous

No data exposure

Unit of transfer is individual I/O– Transfer trigger is receipt of I/O from host– No acknowledgement of I/O to host until remote copy is

updated

Write ordering– I/Os are applied to target in the same order they were

received

High bandwidth and low latency are critical– Distance is limited

RPO – Zero (No data exposure)

5555

Synchronous Model

1

2

34

I/O

I/O

ACK

ACK

1. I/O from host to local storage system2. I/O from local storage system to remote (target) system3. Acknowledgement back from remote to local system4. Acknowledgement from local storage system back to host

5656

Replication Model - Asynchronous Periodic Update

Unit of transfer is Delta Set – What’s changed since last transfer– Transfer trigger can be discrete event or time cycle– I/O is acknowledged to source host immediately

Write ordering is not an issue– Most recent changes are applied to the destination– Updates are applied atomically

RPO – User defined, business driven

Link bandwidth and latency requirements are flexible

5757

Asynchronous Periodic Update Model

1

2

3 4

I/O

ACK

1. I/O from host to storage system2. Acknowledgement from local storage system back to host3. Trigger event4. Delta Sets from local storage system to remote (target) system5. Acknowledgement back from remote to local system

ChunkDelta set

ACK

5

5858

Backup/Restore Options

5959

Backup to Tape Today

Over 80% of all data backed up today goes to tape Typical backup operation

– Full backups usually done weekly– Incremental - backups of all data since the last backup (full or

incremental)– Differential backups-backup of all data that has changed

since the last full backup– For example, a customer performs a full backup of data on

Sunday but only performs an incremental backup of the data each the rest of the week

Customers typically keep multiple “copies” of their backed up data

– Average number of “copies” is 8.5, some at more than 16:1– EMC Best Practices is 4:1or lower

6060

What is Backed up? Operating Environments

– Servers – Desktop PCs– Laptop PCs

Applications– ERP – (i.e. SAP, Oracle Apps, Peoplesoft, etc.)– CRM- (i.e. Siebel, etc)– Databases (Oracle, UDB, MS SQL)– Homegrown (using DB technology, file systems, etc.)– Messaging ( Microsoft Exchange, etc)

Application data– For all of the above– Miscellaneous other end user data

Logs and journals– Application transaction logs, database journals, file system journals

6161

What is Operationally Restored?

Most restores are at the file and volume level– Frequency ranges from several per day to monthly

Full system restores are rare

Most common restores– Email– Files– Application data

6262

EMC Backup-to-Disk Solution: Total Solution with SAN and / or LAN Use SAN and / or LAN

to centralize all backup

Provide higher service levels

Do full backups and incrementals to disk

Regularly copy from disk to tape and move offsite

Extend the life of remaining tape infrastructure

Weekly full backupsNightly incremental backups

Copy from disk to tape and move

offsite

CLARiiONwith ATA

Server with Backup App

Tape

SAN

Data Center

Primary Data

NS600G

Server with Backup App

WAN

6363

Operational Backup-to-Disk Process

Primary Data

Tape

SAN

CLARiiONwith ATA

Application data backed up to disk

Restores from disk

Data migrated to tape

Tape vaulted on / offsite

1 3 42

6464

Introducing CLARiiON Disk LibraryPlug and play

– Supports existing backup environment– Appears as tape library (Fibre Channel attached)– Stores data in native tape format– Complete compatibility with existing operation

High performance – Single stream performance up to 80 MB/s– Up to 425 MB/s sustained performance

Cost effective, reliable, and highly scalable – Data compression (up to 3:1)– Capacity:

• DL300: 12.5 TB / 37.5 TB• DL700: 58 TB / 174 TB

– Built on proven CLARiiON ATA technology

Creates native tape for offsite storage– Policy-based implementation– Automatic single process for moving data from backup

environment to native tape– Offloads creation of second copy from backup server

Application / Backup Hosts

CLARiiON Disk Library

Standard Tape

Library

SAN

6565

CLARiiON Disk Library Implementation

Physical TapeLibraries / Drives

CLARiiONDisk Library

IMPORTEXPORT

LAN

SAN

BackupServer 0010011111

1100110010


1100110010


1100110010

Storage and tape devices can be connected to the CLARiiON Disk Library appliance via Fibre Channel

00101111001010

Emulated tape

Physical tape

Data flow

000111110010

0110101011111010010010

0110101011111010010010

6666

Backup to Disk and Disk Libraries

Disk-to-disk replication– Highest service levels

• Fastest possible backup and recovery• Least impact to production systems

– Highest flexibility• Backup images can be repurposed for testing,

reporting, and more

Tape Library Emulation and backup to disk– Moderate service levels

• Faster backup and recovery than tape– Moderate flexibility

• Disk Libraries support integration with legacy tape environment

• CLARiiON with ATA supports integration with existing CLARiiON primary storage

Tape Libraries– Lowest service levels– Least flexibility

SE

RV

ICE

LE

VE

LS

HIGH

LOW

CLARiiON

CLARiiONDisk Library

Tape

A New Service-Level Option

6767

Example: Storage Management

Storage ManagementStorage Management

81%utilization

78%

utilization

72%

utilization 60%utilization

NetworkedStorage

SAN

NAS

DAS

???

• Data gathering from multiple sources?

• Incomplete, uncorrelated information?

• Different tasks, tools for each vendor?

• Complex and time consuming?

• Making assumptions and mistakes?

Plan and Provision Monitor and Report Device Management

Consistent View of Storage Environment

After

Before

6868

Why Storage Management

Easier to meet service levels– Increase application availability– Expedite problem isolation and resolution– Improve time-to-provision

Helps drive down storage environment costs– Reduce IT staffing costs– Proactive storage and SAN management– Automated provisioning– Current, consistent, correlated information– Increase storage utilization; reclaim capacity

Facilitates compliance with new regulations– Common and consistent storage management information and

processes

6969

Enabling ILM—EMC’s Offering

InformationInfrastructureManagement

Storage ManagementControlCenter Family

Visual FamilyReplication Manager Family

Information and Content ManagementStructured Information

ManagementDatabaseXtender

Enterprise Content ManagementEnterprise Document Mgmt Web Content Mgmt

Digital Asset Mgmt Records Mgmt/ComplianceCollaboration ApplicationXtender

Data MovementData Migration Tools

SAN CopyOnCourse

Intelligent Data ManagementAVALONidm

DiskXtender Family

Protection and RecoveryRemote Replication

SRDF FamilyMirrorViewRepliStor

Celerra Replicator

Local ReplicationTimeFinder Family

SnapViewCelerra SnapSure

Backup / RecoveryNetWorker

AvailabilityPowerPath

AAMCoStandby AAdvanced

Tiered StoragePlatformsSymmetrixCLARiiON

SANConnectrix

NASCelerra

NS SeriesNetWin

Tape Emulation

CLARiiON Disk Library

CASCentera

Tape ADIC Scalar Series

ATATechnology

ServicesPartners

7070

Summary

After completing this session you should:

Be familiar with the components of a computer and how they work to retrieve and store data

Be familiar with RAID technology and understand the different RAID protections

Be familiar with Storage Area Networks and Network Attached Storage as connection options for storage

Be familiar with the different data protection options that are available

Understand how all the pieces fit into the Information Lifecycle Management vision

7171

Closing Slide

storage basics

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