1. © 2006 EMC Corporation. All rights reserved. Business Continuity Section 4 - Introduction

2. © 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 ）

3. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 3 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.

4. © 2006 EMC Corporation. All rights reserved. Business Continuity Overview Module 4.1

5. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 5 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

6. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 6 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

7. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 7 Lost Revenue Know 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 Expenses Temporary 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

8. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 8 Information Availability % Uptime% Downtime Downtime per Year Downtime per Week 98%2%7.3 days3hrs 22 min 99%1%3.65 days1 hr 41 min 99.8%0.2%17 hrs 31 min20 min 10 sec 99.9%0.1%8 hrs 45 min10 min 5 sec 99.99%0.01%52.5 min1 min 99.999%0.001%5.25 min6 sec 99.9999%0.0001%31.5 sec0.6 sec  Protection from data loss  Ensuring data access  Appropriate data security Information availability depends upon robust, functional IT systems.

9. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 9 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 1.5 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

10. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 10 Tape Backup Periodic Replication Recovery Point Objective (RPO) WksDaysHrsMinsSecs Recovery PointRecovery Time Recovery Point Recovery Time Tape Backup Periodic Replication Asynchronous Replication Synchronous Replication SecsMinsHrsDaysWks 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.

11. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 11 Recovery Time Objective (RTO) Recovery Time includes:  Fault detection  Recovering data  Bringing apps back online Global Cluster WksDaysHrsMinsSecs MinsHrsDaysWks Recovery PointRecovery Time Recovery Point Recovery Time Global Cluster Manual Migration Tape Restore 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.

12. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 12 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

13. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 13 Disruptors of Data Availability Disaster (<1% of Occurrences) Natural or man made Flood, fire, earthquake Contaminated building Unplanned Occurrences (13% of Occurrences) Failure Database corruption Component failure Human error Planned Occurrences (87% of Occurrences) Competing workloads Backup, reporting Data warehouse extracts Application and data restore Source: Gartner, Inc.

14. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 14 Causes of Downtime Human Error System Failure Infrastructure Failure Disaster

15. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 15 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.

16. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 16 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

17. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 17 Objectives Analysis Design Develop Train, Test, and Document Implement, Maintain, and Assess Business Continuity Planning Lifecycle

18. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 18 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

19. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 19 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

20. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 20 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

21. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 21 Business Impact Analysis (BIA) # Business Area Affected Impact (1 -5) Probability (1-5) Single Loss Expectancy # Event p/y Loss p/yEst cost of mitigation High Risk SPOF Item 1Entire Company 51$279,056.25$69517$5,800No redundant UPS for Networking/phone equip 2Entire Company 51$279,0660.2$55768$66,456Cisco net backbone switch not redundant 3Entire Company 51$279,0980.2$55619$10,000Relocate net equip to a separate physical rack 4IT-All43$16,0001.018000$80,000Primary dev platforms don’t have failover 5Entire Company 43$16,0000.5$8000$122,000Computer room does not have sufficient UPS capacity to run on single unit 6IT- Intranet/B2B 21$4001.0$1800$5,000No failover for development webserver

22. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 22 User & Application Clients IP Identifying Single Points of Failure Primary Node

23. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 23 HBA Failures HBA Host Switch Storage Port HBA  Configure multiple HBAs, and use multi-pathing software  Protects against HBA failure  Can provide improved performance (vendor dependent) HBA

24. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 24 Switch/Storage Array Port Failures HBA Host Switch Storage Port HBA Port  Configure multiple switches  Make the devices available via multiple storage array ports

25. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 25 Disk Failures HBA Host Switch Storage Port HBA Port  Use some level of RAID

26. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 26 Host Failures HBA Host Switch Storage Port HBA Port Storage Host  Clustering protects against production host failures

27. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 27 Site/Storage Array Failures HBA Host Switch Storage Port HBA Port Storage  Remote replication helps protect against either entire site or storage array failures

28. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 28 User & Application Clients IP Resolving Single Points of Failure Primary Node IP Redundant Network Keep Alive Clustering Software Failover Node Redundant Paths Redundant Disks (RAID 1/RAID 5) Redundant Site Switches Storage Array

29. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 29 Business Continuity Technology Solutions  Local Replication  Remote Replication  Backup/Restore

30. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 30 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.

31. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 31 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.

32. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 32 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.

33. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 33 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

34. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 34 Check Your Knowledge  Which concerns do business continuity solutions address?

35. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 35 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

36. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 36 What is EMC PowerPath? DBMS Managemen t Utils File System Logical Volume Manager Applications Open Systems Host SERVER STORAGE Interconnect Topology SCSIDriverSCSIDriverSCSIDriverSCSIDriverSCSIDriverSCSIDriver SCSI Controller PowerPath  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

37. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 37 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:

38. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 38 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 SD HBA Host Bus Adapter SCSI Driver Storage SERVER STORAGE Interconnect Topology SD HBA PowerPath

39. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 39 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 SD HBA Host Bus Adapter SCSI Driver Storage SERVER STORAGE Interconnect Topology SD HBA PowerPath Filter Driver

40. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 40 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 Bus Adapter SCSI Driver SERVER STORAGE Interconnect Topology

41. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 41 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 SD HBA Host Bus Adapter SCSI Driver Storage SERVER STORAGE Interconnect Topology SD HBA PowerPath

42. © 2006 EMC Corporation. All rights reserved. Storage Systems Architecture - Introduction - 42 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