© 2006 EMC Corporation. All rights reserved. Business Continuity Section 4 - Introduction.

© 2006 EMC Corporation. All rights reserved.

Business ContinuityBusiness Continuity

Section 4 - Introduction

© 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 2

本章目标及内容企业需要提供不间断的服务，而不可避免的各种灾难也

使得数据的容灾与恢复变得极为重要。本章介绍了信息的备份、恢复等基本概念，讲解了在业务连续性的需求下，存储解决方案是如何满足苛刻的业务连续性要求的。另一方面，面对灾难下的数据备份与恢复也是本章主要介绍的内容。

本章内容包括 4 个方面：4.1 业务连续性概述（ Business Continuity Overview ）4.2 备份与恢复（ Backup and Recovery ）4.3 业务连续性：本地复制（ BC: Local Replication ）4.4 业务连续性：远程复制（ BC: Remote Replication ）


Section Objectives

Upon completion of this section, you will be able to:

Describe what business continuity is.

Describe the basic technologies that are enablers of data availability.

Describe basic disaster recovery techniques.

© 2006 EMC Corporation. All rights reserved.

Business Continuity OverviewBusiness Continuity Overview

Module 4.1


Business Continuity Overview

After completing this module, you will be able to:

Define and differentiate between Business Continuity and Disaster Recovery

Differentiate between Disaster Recovery and Disaster Restart

Define terminology such as Recovery Point Objective and Recovery Time Objective

Give a high level description of Business Continuity Planning

Identify Single Points of Failure and describe solutions to eliminate them


What is Business Continuity?

Business Continuity is the preparation for, response to, and recovery from an application outage that adversely affects business operations

Business Continuity Solutions address systems unavailability, degraded application performance, or unacceptable recovery strategies


Lost RevenueKnow the downtime costs (per hour, day, two days...)• Number of employees

impacted (x hours out * hourly rate)

Damaged Reputation

• Customers• Suppliers• Financial markets• Banks• Business partners

Financial Performance

• Revenue recognition• Cash flow• Lost discounts (A/P)• Payment guarantees• Credit rating• Stock price

Other ExpensesTemporary employees, equipment rental, overtime costs, extra shipping costs, travel expenses...

Why Business Continuity

• Direct loss• Compensatory payments• Lost future revenue• Billing losses• Investment losses

Lost Productivity


Information Availability

% Uptime % DowntimeDowntime per

YearDowntime per

Week

98% 2% 7.3 days 3hrs 22 min

99% 1% 3.65 days 1 hr 41 min

99.8% 0.2% 17 hrs 31 min 20 min 10 sec

99.9% 0.1% 8 hrs 45 min 10 min 5 sec

99.99% 0.01% 52.5 min 1 min

99.999% 0.001% 5.25 min 6 sec

99.9999% 0.0001% 31.5 sec 0.6 sec

Protection from data loss

Ensuring data access

Appropriate data security

Information availability depends upon robust, functional IT systems.


Importance of Business Continuity and Planning

Millions of US Dollars per Hour in Lost Revenue

6.5

3.6

2.8

2.6

2.0

1.6

1.6

1.5

1.3

1.2

1.1

Retail brokerage

Point of sale

Energy

Credit card sales authorization

Telecommunications

Call location

Manufacturing

Financial institutions

Information technology

Insurance

Retail

Source Meta Group, 2005


Tap

e B

acku

p

Per

iod

ic

Rep

licat

ion

Recovery Point Objective (RPO)

Wks Days Hrs Mins Secs

Recovery Point Recovery TimeRecovery Point Recovery Time

Tap

e B

acku

p

Per

iod

ic

Rep

licat

ion

Asy

nch

ron

ou

s R

eplic

atio

nA

syn

chro

no

us

R

eplic

atio

n

Syn

chro

no

us

Rep

licat

ion

Syn

chro

no

us

R

eplic

atio

n

Secs Mins Hrs Days Wks

is the point in time to which systems and data must be recovered after an outage. This defines the amount of data loss a business can endure.


Recovery Time Objective (RTO)

Recovery Time includes:

Fault detection

Recovering data

Bringing apps back online

Glo

bal

C

lust

er

Wks Days Hrs Mins Secs Secs Mins Hrs Days Wks

Recovery Point Recovery TimeRecovery Point Recovery Time

Glo

bal

C

lust

er

Man

ual

M

igra

tio

nM

anu

al

Mig

rati

on

Tap

e R

esto

reT

ape

Res

tore

is the period of time within which systems, applications, or functions must be recovered after an outage. This defines the amount of downtime that a business can endure, and survive.


Disaster Recovery versus Disaster Restart

Most business critical applications have some level of data interdependencies

Disaster recovery– Restoring previous copy of data and applying logs to that copy to bring it to

a known point of consistency

– Generally implies the use of backup technology

– Data copied to tape and then shipped off-site

– Requires manual intervention during the restore and recovery processes

Disaster restart – Process of restarting mirrored consistent copies of data and applications

– Allows restart of all participating DBMS to a common point of consistency utilizing automated application of recovery logs during DBMS initialization

– The restart time is comparable to the length of time required for the application to restart after a power failure


Disruptors of Data Availability

Disaster (<1% of Occurrences)

Natural or man made Flood, fire, earthquakeContaminated building

Unplanned Occurrences (13% of Occurrences)

FailureDatabase corruptionComponent failureHuman error

Planned Occurrences (87% of Occurrences)

Competing workloads Backup, reportingData warehouse extractsApplication and data restore

Source: Gartner, Inc.


Causes of Downtime

Human Error

System Failure

Infrastructure Failure

Disaster


Business Continuity vs. Disaster Recovery

Business Continuity has a broad focus on prevention:– Predictive techniques to identify risks

– Procedures to maintain business functions

Disaster Recovery focuses on the activities that occur after an adverse event to return the entity to ‘normal’ functioning.


Business Continuity Planning (BCP)

Includes the following activities:

Identifying the mission or critical business functions

Collecting data on current business processes

Assessing, prioritizing, mitigating, and managing risk– Risk Analysis

– Business Impact Analysis (BIA)

Designing and developing contingency plans and disaster recovery plan (DR Plan)

Training, testing, and maintenance


Objectives

Train, Test, and

Document

Implement,

Maintain, and

Assess

Analysis

Design

Develop

Business Continuity Planning Lifecycle


BCP Lifecycle

1. Objectives– Determine business continuity requirements and

objectives including scope and budget

– Team selection (include all areas of the business and subject matter expertise (internal/external)

– Create the project plan


BCP Lifecycle

2. Perform analysis– Collect information on data, business processes,

infrastructure supports, dependencies, frequency of use

– Identify critical needs and assign recovery priorities.

– Create a risk analysis (areas of exposure) and mitigation strategies wherever possible.

– Create a Business Impact Analysis (BIA)

– Create a Cost/benefit analysis – identify the cost (per hour/day, etc.) to the business when data is unavailable.

– Evaluate Options


BCP Lifecycle

3. Design and Develop the BCP/Strategies– Evaluate options

– Define roles/responsibilities

– Develop contingency scenarios

– Develop emergency response procedures

– Detail recovery, resumption, and restore procedures

– Design data protection strategies and develop infrastructure

– Implement risk management/mitigation procedures

4. Train, test, and document

5. Implement, maintain, and assess


Business Impact Analysis (BIA)

# Business Area Affected

Impact (1 -5)

Probability (1-5)

Single Loss Expectancy

# Event p/y

Loss p/y Est cost of mitigation

High Risk SPOF Item

1 Entire Company

5 1 $279,056 .25 $69517 $5,800 No redundant UPS for Networking/phone equip

2 Entire Company

5 1 $279,066 0.2 $55768 $66,456 Cisco net backbone switch not redundant

3 Entire Company

5 1 $279,098 0.2 $55619 $10,000 Relocate net equip to a separate physical rack

4 IT-All 4 3 $16,000 1.0 18000 $80,000 Primary dev platforms don’t have failover

5 Entire Company

4 3 $16,000 0.5 $8000 $122,000 Computer room does not have sufficient UPS capacity to run on single unit

6 IT- Intranet/B2B

2 1 $400 1.0 $1800 $5,000 No failover for development webserver


User & Application Clients

IP

Identifying Single Points of Failure

Primary Node


HBA Failures

HBAHBA

Host

Switch

Storage

PortPortHBA

Configure multiple HBAs, and use multi-pathing software

Protects against HBA failure

Can provide improved performance (vendor dependent)

HBA


Switch/Storage Array Port Failures

HBAHBA

HostSwitch

Storage

PortPortHBAHBA

PortPort

Configure multiple switches

Make the devices available via multiple storage array ports


Disk Failures

HBAHBA

HostSwitch

Storage

PortPortHBAHBA

PortPort

Use some level of RAID


Host Failures

HBAHBA

HostSwitch

Storage

PortPortHBAHBA

PortPort

Storage

Host

Clustering protects against production host failures


Site/Storage Array Failures

HBAHBA

HostSwitch

Storage

PortPortHBAHBA

PortPort

Storage

Remote replication helps protect against either entire site or storage array failures


User & Application Clients

IP

Resolving Single Points of Failure

Primary Node

IP

Redundant Network

Kee

p A

live

Clustering Software

Failover Node

Redundant PathsRedundant Disks (RAID 1/RAID 5)

Redundant Site

Switches

Storage Array Storage Array


Business Continuity Technology Solutions

Local Replication

Remote Replication

Backup/Restore


Local Replication

Data from the production devices is copied over to a set of target (replica) devices.

After some time, the replica devices will contain identical data as those on the production devices.

Subsequently copying of data can be halted. At this point-in-time, the replica devices can be used independently of the production devices.

The replicas can then be used for restore operations in the event of data corruption or other events.

Alternatively the data from the replica devices can be copied to tape. This off-loads the burden of backup from the production devices.


Local Replication

Data from the production devices is copied over to a set of target (replica) devices.

After some time, the replica devices will contain identical data as those on the production devices.

Subsequently copying of data can be halted. At this point-in-time, the replica devices can be used independently of the production devices.

The replicas can then be used for restore operations in the event of data corruption or other events.

Alternatively the data from the replica devices can be copied to tape. This off-loads the burden of backup from the production devices.


Backup/Restore

Backup to tape has been the predominant method for ensuring data availability and business continuity.

Low cost, high capacity disk drives are now being used for backup to disk. This considerably speeds up the backup and the restore process.

Frequency of backup will be dictated by defined RPO/RTO requirements as well as the rate of change of data.


Module Summary

Key concepts covered in this module are:

Importance of Business Continuity

Types of outages and their impact to businesses

Business Continuity Planning and Disaster Recovery

Definitions of RPO and RTO

Difference between Disaster Recovery and Disaster Restart

Identifying and eliminating Single Points of Failure


Check Your Knowledge

Which concerns do business continuity solutions address?


Apply Your Knowledge

After completing this case study, you will be able to:

Describe EMC PowerPath

Discuss the features and benefits of PowerPath in storage environments

Explain how PowerPath achieves transparent recovery


What is EMC PowerPath?

DBMSDBMS ManagemManagementent

UtilsUtilsFile File SystemSystemLogical Volume Logical Volume

ManagerManager

ApplicationsApplications

Open Systems

Host

SE

RV

ER

ST

OR

AG

E InterconnectTopology

SCSISCSIDriverDriver






SCSISCSIControllerController






PowerPathPowerPath

Host Based Software

Resides between application and SCSI device driver

Provides Intelligent I/O path management

Transparent to the application

Automatic detection and recovery from host-to-array path failures


PowerPath Features

Multiple paths, for higher availability and performance

Dynamic multipath load balancing

Proactive path testing and automatic path recovery

Automatic path failover

Online path configuration and management

High-availability cluster support

PowerPath Delivers:


PowerPath Configuration

All volumes are accessible through all paths

Maximum 32 paths to a logical volume

Interconnect support for – SAN

– SCSI

– iSCSI

Host Application(s)

HBA HBA

SD SDSD

HBA Host BusAdapter

SCSIDriver

Storage

SE

RV

ER

ST

OR

AG


SD

HBA

PowerPath


The PowerPath Filter Driver

Platform independent base driver

Applications direct I/O to PowerPath

PowerPath directs I/O to optimal path based on current workload and path availability

When a path fails PowerPath chooses another path in the set

Host Application(s)

HBA HBA

SD SDSD

HBA Host BusAdapter

SCSIDriver

Storage

SE

RV

ER

ST

OR

AG


SD

HBA

PowerPath Filter Driver


Path Fault without PowerPath

In most environments, a host will have multiple paths to the Storage System

Volumes are spread across all available paths

Each volume has a single path

Host adapter and cable connections are single points of failure

Work load not balanced among all paths

Storage

Host Application(s)

SD

HBA

SD

HBA

SD

HBA

SD

HBA Host BusAdapter

SCSIDriver

SE

RV

ER

ST

OR

AG



Path Fault with PowerPath

If a host adapter, cable, or channel director/Storage Processor fails, the device driver returns a timeout to PowerPath

PowerPath responds by taking the path offline and re-driving I/O through an alternate path

Subsequent I/Os use surviving path(s)

Application is unaware of failure

Host Application(s)

HBA HBA

SD SDSD

HBA Host BusAdapter

SCSIDriver

Storage

SE

RV

ER

ST

OR

AG


SD

HBA

PowerPath


Module Summary

Key points covered in this module:

PowerPath is server based software that provides multiple paths between the host bus adapter and the Storage Subsystem– Redundant paths eliminate host adapter, cable connection, and

channel adapters as single points of failures and increase availability

– Improves performance by dynamically balancing the workload across all available paths

– Application transparent

Enhances data availability and accessibility

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