- Management Reference Guide
- Table of Contents
- Introduction
- Strategic Management
- Establishing Goals, Objectives, and Strategies
- Aligning IT Goals with Corporate Business Goals
- Utilizing Effective Planning Techniques
- Developing Worthwhile Mission Statements
- Developing Worthwhile Vision Statements
- Instituting Practical Corporate Values
- Budgeting Considerations in an IT Environment
- Introduction to Conducting an Effective SWOT Analysis
- IT Governance and Disaster Recovery, Part One
- IT Governance and Disaster Recovery, Part Two
- Customer Management
- Identifying Key External Customers
- Identifying Key Internal Customers
- Negotiating with Customers and Suppliers—Part 1: An Introduction
- Negotiating With Customers and Suppliers—Part 2: Reaching Agreement
- Negotiating and Managing Realistic Customer Expectations
- Service Management
- Identifying Key Services for Business Users
- Service-Level Agreements That Really Work
- How IT Evolved into a Service Organization
- FAQs About Systems Management (SM)
- FAQs About Availability (AV)
- FAQs About Performance and Tuning (PT)
- FAQs About Service Desk (SD)
- FAQs About Change Management (CM)
- FAQs About Configuration Management (CF)
- FAQs About Capacity Planning (CP)
- FAQs About Network Management
- FAQs About Storage Management (SM)
- FAQs About Production Acceptance (PA)
- FAQs About Release Management (RM)
- FAQs About Disaster Recovery (DR)
- FAQs About Business Continuity (BC)
- FAQs About Security (SE)
- FAQs About Service Level Management (SL)
- FAQs About Financial Management (FN)
- FAQs About Problem Management (PM)
- FAQs About Facilities Management (FM)
- Process Management
- Developing Robust Processes
- Establishing Mutually Beneficial Process Metrics
- Change Management—Part 1
- Change Management—Part 2
- Change Management—Part 3
- Audit Reconnaissance: Releasing Resources Through the IT Audit
- Problem Management
- Problem Management–Part 2: Process Design
- Problem Management–Part 3: Process Implementation
- Business Continuity Emergency Communications Plan
- Capacity Planning – Part One: Why It is Seldom Done Well
- Capacity Planning – Part Two: Developing a Capacity Planning Process
- Capacity Planning — Part Three: Benefits and Helpful Tips
- Capacity Planning – Part Four: Hidden Upgrade Costs and
- Improving Business Process Management, Part 1
- Improving Business Process Management, Part 2
- 20 Major Elements of Facilities Management
- Major Physical Exposures Common to a Data Center
- Evaluating the Physical Environment
- Nightmare Incidents with Disaster Recovery Plans
- Developing a Robust Configuration Management Process
- Developing a Robust Configuration Management Process – Part Two
- Automating a Robust Infrastructure Process
- Improving High Availability — Part One: Definitions and Terms
- Improving High Availability — Part Two: Definitions and Terms
- Improving High Availability — Part Three: The Seven R's of High Availability
- Improving High Availability — Part Four: Assessing an Availability Process
- Methods for Brainstorming and Prioritizing Requirements
- Introduction to Disk Storage Management — Part One
- Storage Management—Part Two: Performance
- Storage Management—Part Three: Reliability
- Storage Management—Part Four: Recoverability
- Twelve Traits of World-Class Infrastructures — Part One
- Twelve Traits of World-Class Infrastructures — Part Two
- Meeting Today's Cooling Challenges of Data Centers
- Strategic Security, Part One: Assessment
- Strategic Security, Part Two: Development
- Strategic Security, Part Three: Implementation
- Strategic Security, Part Four: ITIL Implications
- Production Acceptance Part One – Definition and Benefits
- Production Acceptance Part Two – Initial Steps
- Production Acceptance Part Three – Middle Steps
- Production Acceptance Part Four – Ongoing Steps
- Case Study: Planning a Service Desk Part One – Objectives
- Case Study: Planning a Service Desk Part Two – SWOT
- Case Study: Implementing an ITIL Service Desk – Part One
- Case Study: Implementing a Service Desk Part Two – Tool Selection
- Ethics, Scandals and Legislation
- Outsourcing in Response to Legislation
- Supplier Management
- Identifying Key External Suppliers
- Identifying Key Internal Suppliers
- Integrating the Four Key Elements of Good Customer Service
- Enhancing the Customer/Supplier Matrix
- Voice Over IP, Part One — What VoIP Is, and Is Not
- Voice Over IP, Part Two — Benefits, Cost Savings and Features of VoIP
- Application Management
- Production Acceptance
- Distinguishing New Applications from New Versions of Existing Applications
- Assessing a Production Acceptance Process
- Effective Use of a Software Development Life Cycle
- The Role of Project Management in SDLC— Part 2
- Communication in Project Management – Part One: Barriers to Effective Communication
- Communication in Project Management – Part Two: Examples of Effective Communication
- Safeguarding Personal Information in the Workplace: A Case Study
- Combating the Year-end Budget Blitz—Part 1: Building a Manageable Schedule
- Combating the Year-end Budget Blitz—Part 2: Tracking and Reporting Availability
- References
- Developing an ITIL Feasibility Analysis
- Organization and Personnel Management
- Optimizing IT Organizational Structures
- Factors That Influence Restructuring Decisions
- Alternative Locations for the Help Desk
- Alternative Locations for Database Administration
- Alternative Locations for Network Operations
- Alternative Locations for Web Design
- Alternative Locations for Risk Management
- Alternative Locations for Systems Management
- Practical Tips To Retaining Key Personnel
- Benefits and Drawbacks of Using IT Consultants and Contractors
- Deciding Between the Use of Contractors versus Consultants
- Managing Employee Skill Sets and Skill Levels
- Assessing Skill Levels of Current Onboard Staff
- Recruiting Infrastructure Staff from the Outside
- Selecting the Most Qualified Candidate
- 7 Tips for Managing the Use of Mobile Devices
- Useful Websites for IT Managers
- References
- Automating Robust Processes
- Evaluating Process Documentation — Part One: Quality and Value
- Evaluating Process Documentation — Part Two: Benefits and Use of a Quality-Value Matrix
- When Should You Integrate or Segregate Service Desks?
- Five Instructive Ideas for Interviewing
- Eight Surefire Tips to Use When Being Interviewed
- 12 Helpful Hints To Make Meetings More Productive
- Eight Uncommon Tips To Improve Your Writing
- Ten Helpful Tips To Improve Fire Drills
- Sorting Out Today’s Various Training Options
- Business Ethics and Corporate Scandals – Part 1
- Business Ethics and Corporate Scandals – Part 2
- 12 Tips for More Effective Emails
- Management Communication: Back to the Basics, Part One
- Management Communication: Back to the Basics, Part Two
- Management Communication: Back to the Basics, Part Three
- Asset Management
- Managing Hardware Inventories
- Introduction to Hardware Inventories
- Processes To Manage Hardware Inventories
- Use of a Hardware Inventory Database
- References
- Managing Software Inventories
- Business Continuity Management
- Ten Lessons Learned from Real-Life Disasters
- Ten Lessons Learned From Real-Life Disasters, Part 2
- Differences Between Disaster Recovery and Business Continuity , Part 1
- Differences Between Disaster Recovery and Business Continuity , Part 2
- 15 Common Terms and Definitions of Business Continuity
- The Federal Government’s Role in Disaster Recovery
- The 12 Common Mistakes That Cause BIAs To Fail—Part 1
- The 12 Common Mistakes That Cause BIAs To Fail—Part 2
- The 12 Common Mistakes That Cause BIAs To Fail—Part 3
- The 12 Common Mistakes That Cause BIAs To Fail—Part 4
- Conducting an Effective Table Top Exercise (TTE) — Part 1
- Conducting an Effective Table Top Exercise (TTE) — Part 2
- Conducting an Effective Table Top Exercise (TTE) — Part 3
- Conducting an Effective Table Top Exercise (TTE) — Part 4
- The 13 Cardinal Steps for Implementing a Business Continuity Program — Part One
- The 13 Cardinal Steps for Implementing a Business Continuity Program — Part Two
- The 13 Cardinal Steps for Implementing a Business Continuity Program — Part Three
- The 13 Cardinal Steps for Implementing a Business Continuity Program — Part Four
- The Information Technology Infrastructure Library (ITIL)
- The Origins of ITIL
- The Foundation of ITIL: Service Management
- Five Reasons for Revising ITIL
- The Relationship of Service Delivery and Service Support to All of ITIL
- Ten Common Myths About Implementing ITIL, Part One
- Ten Common Myths About Implementing ITIL, Part Two
- Characteristics of ITIL Version 3
- Ten Benefits of itSMF and its IIL Pocket Guide
- Translating the Goals of the ITIL Service Delivery Processes
- Translating the Goals of the ITIL Service Support Processes
- Elements of ITIL Least Understood, Part One: Service Delivery Processes
- Case Study: Recovery Reactions to a Renegade Rodent
- Elements of ITIL Least Understood, Part Two: Service Support
- Case Studies
- Case Study — Preparing for Hurricane Charley
- Case Study — The Linux Decision
- Case Study — Production Acceptance at an Aerospace Firm
- Case Study — Production Acceptance at a Defense Contractor
- Case Study — Evaluating Mainframe Processes
- Case Study — Evaluating Recovery Sites, Part One: Quantitative Comparisons/Natural Disasters
- Case Study — Evaluating Recovery Sites, Part Two: Quantitative Comparisons/Man-made Disasters
- Case Study — Evaluating Recovery Sites, Part Three: Qualitative Comparisons
- Case Study — Evaluating Recovery Sites, Part Four: Take-Aways
- Disaster Recovery Test Case Study Part One: Planning
- Disaster Recovery Test Case Study Part Two: Planning and Walk-Through
- Disaster Recovery Test Case Study Part Three: Execution
- Disaster Recovery Test Case Study Part Four: Follow-Up
- Assessing the Robustness of a Vendor’s Data Center, Part One: Qualitative Measures
- Assessing the Robustness of a Vendor’s Data Center, Part Two: Quantitative Measures
- Case Study: Lessons Learned from a World-Wide Disaster Recovery Exercise, Part One: What Did the Team Do Well
- (d) Case Study: Lessons Learned from a World-Wide Disaster Recovery Exercise, Part Two
There are several methods available for recovering data that has been altered, deleted, damaged, or otherwise made inaccessible. The recovery techniques used depend on the manner in which the data was backed up. Table 1 lists four common types of data backups. The first three are referred to as physical backups because operating system software or specialized program products copy the data as it physically resides on the disk without regard to database structures or logical organization—it is purely a physical backup. The fourth is called a logical backup because database management software reads—or backs up—logical parts of the database, such as tables, schemas, data dictionaries, or indexes, and then writes the output to binary files. This may be done for the full database, for individual users, or for specific tables.
Physical offline backups require that all online systems, applications, and databases residing on a volume being backed up be shut down prior to starting the backup process. Performing several full volume backups of high-capacity disk drives may take many hours to complete and are normally done on weekends when systems can be shut down for long periods of time. Incremental backups also require systems and databases to be shut down, but for much shorter periods of time. Since only the data that has changed since the last backup is what is copied, incremental backups can usually be completed within a few hours if done on a nightly basis.
Table 1 Types of Data Backups
|
Type of Backup |
Alternate Names |
|
1. Physical full backup |
Cold backup Full volume backup Full offline backup |
|
2. Physical incremental backup |
Incremental backup Incremental offline backup |
|
3. Physical online backup |
Online backup Hot backup Archive backup |
|
4. Logical backup |
Exporting files Exporting files into binary files |
A physical online backup is a powerful backup technique that offers two very valuable and distinct benefits:
- Databases can remain open to users during the backup process.
- Recovery can be accomplished back to the last transaction processed.
The database environment must be running in an archive mode for online backups to occur properly. This means that fully filled log files, prior to being written over, are first written to an archive file. During online backups, table files are put into a backup state one at a time to enable the operating system to back up the data associated with it. Any changes made during the backup process are temporarily stored in logs files and then brought back to their normal state after that particular table file has been backed up.
Full recovery is accomplished by restoring the last full backup and the incremental backups taken since the last full backup and then doing a forward recovery utilizing the archive and log tapes. For Oracle databases, the logging is referred to as redo files; when these files are full, they are copied to archive files before being written over for continuous logging. Sybase, IBM's Database2 (DB2) and Microsoft's SQLSERVER have similar logging mechanisms using checkpoints and transaction logs. Log files can also be shipped or transported to other locations to aid in disaster recovery.
Replication is another form of backup in which highly critical data is copied in close to real time to a remote location. Replication intervals can vary from just a few minutes to several hours. I assisted three recent clients in implementing replication schemes that were similar in concept but different in application. One replicated its critical data between Los Angeles and Las Vegas every thirty minutes. Another replicated theirs every twenty minutes from coast to coast. The third company replicated their crucial data every fifteen minutes between Southern California and Denver. The point here is that replication schemes will vary depending on a company's requirements and the amount of costs they are willing to incur.
Logical backups are less complicated and more time consuming to perform than physical backups. There are three advantages to performing logical backups in concert with physical backups:
- Exports can be made online enabling 24/7 applications and databases to remain operational during the copying process.
- Small portions of a database can be exported and imported, efficiently enabling maintenance to be performed on only the data required.
- Exported data can be imported into databases or schemas at a higher version level than the original database, allowing for testing at new software levels.
Another approach to safeguarding data becoming more prevalent today is thedisk-to-disk backup. As the size of critical databases continues to grow, and as allowable backup windows continue to shrink, the advantages of this approach are rapidly helping to justify its obvious costs. The first advantage is the significant reduction in backup and recovery time. Copying directly to disk is orders of magnitude faster than copying to tape. This benefit also applies to online backups, which, while allowing databases to be open and accessible during backup processing, still incur a performance hit that is noticeably reduced by this method.
Another advantage of disk-to-disk backups is that the stored copy can be used for other purposes, such as testing or report generation which, if done with the original data, could impact database performance. Finally, this approach can actually cost justify tape backups. Copying the second stored disk files to tape can be scheduled at any time, provided it ends prior to the beginning of the next disk backup. It may even reduce investment in tape equipment, which can offset the costs of additional disks.
A thorough understanding of the requirements and the capabilities of data backups, restores, and recovery is necessary for implementing a robust storage management process. Several other backup considerations need to be kept in mind when designing such a process, and these are listed in Table 2.
|
1. Backup window 2. Restore times 3. Expiration dates 4. Retention periods 5. Recycle periods 6. Generation data groups 7. Offsite retrieval times 8. Tape density 9. Tape format 10. Tape packaging 11. Shelf life 12. Automation techniques |
Table 2 Data Backup Considerations
There are three key questions that need to be answered at the outset:
- How much nightly backup window is available?
- How long will it take to perform nightly backups?
- Back to what point in time should recovery be made?
If the time needed to back up all the required data on a nightly basis exceeds the offline backup window, then some form of online backup will be necessary. The method of recovery that will be used will depend on whether data is to be restored back to the last incremental backup or back to the last transaction completed.
Expiration dates, retention periods, and recycling periods are related issues pertaining to the length of time data is intended to stay in existence. Weekly and monthly application jobs may create temporary data files that are designed to expire one week or one month, respectively, after the data was generated. Other files may need to be retained for several years for auditing purposes or for government regulations. Backup files on tape also fall into these categories. Expiration dates and retention periods are specified in the job control language that describes how these various files will be created. Recycle periods relate to the elapsed time before backup tapes are reused.
A generation data group (GDG) is a mainframe mechanism for creating new versions of a data file that would be similar to that created with backup jobs. The advantage of this is the ability to restore back to a specific day with simple parameter changes to the job control language. Offsite retrieval time is the maximum contracted time that the offsite tape storage provider is allowed to physically bring tapes to the data center from the time of notification.
Tape density, format, and packaging relate to characteristics that may change over time and consequently change recovery procedures. Density refers to the compression of bits as they are stored on the tape; it will increase as technology advances and equipment is upgraded. Format refers to the number and configuration of tracks on the tape. Packaging refers to the size and shape of the enclosures used to house the tapes.
The shelf life of magnetic tape is sometimes overlooked and can become problematic for tapes with retention periods exceeding five or six years. Temperature, humidity, handling, frequent changes in the environment, the quality of the tape, and other factors can influence the actual shelf life of any given tape, but five years is a good rule of thumb to use for recopying long-retained tapes.
Mechanical tape loaders, automated tape library systems, and movable tape rack systems can all add a degree of labor-saving automation to the storage management process. As with any process automation, thorough planning and process streamlining need to precede the implementation of the automation.
This concludes the four-part series on storage management. It covered the areas storage capacities, performance, reliability and recoverability. Other sections of this Management Guide that are related to storage management include those on Capacity Planning and Improving High Availability.