chapter 9 system maintenance

CHAPTER 9

SYSTEM MAINTENANCE

Chapter Objectives 2

Explain the systems support and security phase

Describe user support activities, including user training and help desks

Define the four types of maintenance Explain various techniques for

managing systems maintenance and support

Chapter Objectives3

Describe techniques for measuring, managing, and planning system performance

Explain risk management concepts Assess system security at six levels:

physical security, network security, application security, file security, user security, and procedural security

Chapter Objectives4

Describe backup and disaster recovery List factors indicating that a system has

reached the end of its useful life Assess future challenges and

opportunities for IT professionals Develop a strategic plan for career

advancement and strong IT credentials

Introduction5

Managing systems support and security involves three main concerns: user expectations, system performance, and security requirements

Successful, robust systems often need the most support

In most organizations, more than half of all IT department effort goes into supporting existing systems

Overview6

The systems operation, support, and security phase begins when a system becomes operational and continues until the system reaches the end of its useful life

After delivering the system, the IT team focuses on support and maintenance tasks

User Support7

User Training Additionally, new employees must be

trained on the company’s information systems

User training package Training users about system changes is

similar to initial training Objective is to show users how the system

can help them perform their jobs

User Support8

Help Desks Often called an information center (IC) Enhance productivity and improve

utilization of a company’s information resources

User Support9

Help Desk Might have to perform the following tasks:

Show a user how to create a data query or report that displays specific business information

Resolve network access or password problems Demonstrate an advanced feature of a system

or a commercial package Help a user recover damaged data

User Support10

Help Desk In addition to functioning as a valuable link

between IT staff and users, the help desk is a central contact point for all IT maintenance activities

Can utilize many types of automated support

Maintenance Tasks11

The systems operation, support and security phase is an important component of TCO (total cost of ownership) because ongoing maintenance expenses can determine the economic life of a system

Operational costs Maintenance expenses Maintenance activities

Maintenance Tasks12

Four types of maintenance task can be identified

Corrective maintenance Adaptive maintenance Perfective maintenance Preventive maintenance

Maintenance Tasks13

[1] Corrective Maintenance Diagnoses and corrects errors in an

operational system Respond to errors in various ways,

depending on nature and severity of the problem

In a typical procedure, a user submits a systems request that is evaluated, prioritized and scheduled

Maintenance Tasks14

[1] Corrective Maintenance For more serious situations, a user submits

a systems request with supporting evidence

Worst-case situation is a system failure

When the system is operational again, the maintenance team determines the cause, analyzes the problem, and designs a permanent solution

Maintenance Tasks15

[2] Adaptive Maintenance Adds enhancements to an operational

system and makes the system easier to use

The procedure for minor adaptive maintenance is similar to routine corrective maintenance

Can be more difficult than new systems development because the enhancements must work within the constraints of an existing system

Maintenance Tasks16

[3] Perfective Maintenance Involves changing an operational

system to make it more efficient, reliable and maintainable

Can improve system reliability Cost-effective during the middle of the

system’s operational life

Maintenance Tasks17

[3] Perfective Maintenance Software reengineering Programs that need a large number of

maintenance changes usually are good candidates for reengineering

The more a program changes, the more likely it is to become inefficient and difficult to maintain

Maintenance Tasks18

[4] Preventive Maintenance Requires analysis of areas where

trouble is likely to occur IT department normally initiates

preventative maintenance Often results in increased user satisfaction,

decreased downtime, and reduced TCO Sometimes does not receive the high

priority that it deserves

Maintenance Management19

Requires effective management, quality assurance and cost control

To achieve these goals, companies use various strategies

In addition, firms use version control and baselines to track system releases and analyze the system’s life cycle


The Maintenance Team System administrator Systems analysts

Analysis Synthesis

Programmers Applications programmer Systems programmer Database programmer Programmer/analyst


The Maintenance Team Organizational issues

IT managers often divide systems analysts and programmers into two groups: one group performs new system development, and the other group handles maintenance

Many analysts feel that maintenance work is less attractive than developing new systems

One disadvantage of rotation is that it increases overhead costs


Maintenance Requests Involve a series of steps All work must be covered by a specific

request Initial determination The systems review committee Task completion User notification


Establishing Priorities In many companies, systems review

committee separates maintenance requests from new systems development requests

Some IT managers believe that evaluating all projects together leads to the best possible decisions

Object is to have a procedure that balances new development and necessary maintenance work


Configuration Management Configuration management (CM)

Configuration management (CM) is a process for controlling changes in system requirements during the development phases of the SDLC.

As enterprise-wide information systems grow more complex, configuration management becomes critical

Also helps to organize and handle documentation


Maintenance Releases Maintenance release methodology:

numbering system Maintenance release A numbering pattern distinguishes the

different released Reduces the documentation burden But new features or upgrades are

available less often Service packs


Version Control Version control Archived Essential part of system documentation Companies can purchase software such as

Serena


Baselines Systems analysts use baselines as yardsticks to

document features and performance during the systems development process

Functional baseline: beginning of the project Sys. Req. & design constraints

Allocated baseline: design phase Testing, verification of sys. req. & features

Product baseline: system operation Performance results & UAT

System Performance Management

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Today, companies use complex networks and client/server systems to support business needs

To ensure satisfactory support for business operations, the IT department must manage system faults and interruptions, measure system performance and workload, and anticipate future needs


29

Fault Management The more complex the system, the more

difficult it can be to analyze symptoms and isolate a cause

The best strategy is to prevent problems by monitoring system performance and workload


30

Performance and Workload Measurement Benchmark testing Metrics Response time Bandwidth and throughput

Kbps (kilobits per second) Mbps (megabits per second) Gbps (gigabits per second)


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Performance and Workload Measurement Turnaround time The IT department often measures

response time, bandwidth, throughput, and turnaround time to evaluate system performance both before and after changes to the system or business information requirements

Management uses current performance and workload data as input for the capacity planning process


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Capacity Planning What-if analysis You need detailed information about the

number of transactions; the daily, weekly, or monthly transaction patterns; the number of queries; and the number, type, and size of all generated reports


33

Capacity Planning Most important, you need an accurate

forecast of future business activities If new business functions or requirements

are predicted, you should develop contingency plans based on input from users and management


34

System Maintenance Tools Many CASE tools include system

evaluation and maintenance features In addition to CASE tools, you also can use

spreadsheet and presentation software to calculate trends, perform what-if analyses, and create attractive charts and graphs to display the results

System Security Overview35

Security is a vital part of every computer system

System Security Concepts CIA triangle Integrity Availability Security policy


Risk Management Absolute security is not a realistic goal Risk identification - exploit Risk assessment - risk Risk control

Avoidance, mitigation, transference, acceptance


Attacker Profiles and Attacks An attack might be launched by a

disgruntled employee, or a hacker who is 10,000 miles away

Attackers break into a system to cause damage, steal information, or gain recognition, among other reasons

Security Levels38

Must consider six separate but interrelated levels

Physical Security First level of security concerns the physical

environment Physical access to a computer represents

an entry point into the system and must be controlled and protected

Security Levels39

Physical Security Operations center security

Biometric scanning systems Servers and desktop computers

Keystroke logger Tamper-evident cases BIOS-level password Boot-level password Power-on password Uninterruptible power supply (UPS)

Security Levels40

Physical Security Notebook computers

Select an operating system that allows secure logons and BIOS-level passwords

Mark or engrave the computer’s case Consider notebook models that have a built-in

fingerprint reader many notebook computers have a Universal

Security Slot (USS) Back up all vital data

Security Levels41

Physical Security Notebook computers

Use tracking software While traveling, try to be alert to potential high-

risk situations Establish stringent password protection policies

Security Levels42

Network Security Network Network interface Encrypted Encrypting network traffic

Unencrypted – plain text Private key encryption Public key encryption (PKE)

Security Levels43

Network Security Wireless networks

Wired Equivalent Privacy (WEP) Wi-Fi Protected Access (WPA) WPA2 IEEE 802.11i WPA2 is compatible with WPA, so companies

easily can migrate to the new security standard

Security Levels44

Network Security Private networks

Private network Virtual private networks

Virtual private network (VPN) Tunnel

Security Levels45

Network Security Ports and services

Port Service Port scans Denial of service (DOS) Distributed denial of service (DDOS)

Security Levels46

Network Security Firewalls

Firewall Firewalls can be configured to detect and

respond to denial-of-service attacks, port scans, and other suspicious activity

Network intrusion detection – network intrusion detection system (NIDS)

Security Levels47

Application Security Services

Security hole Hardening

Malware Application permissions

Administrator – super-user User rights - permissions

Security Levels48

Application Security Input validation Patches and updates

Patches Third-party software Automatic update service

Software Logs Log

Security Levels49

File Security Permissions

Read a file Write a file Execute a file Read a directory Write a directory

User Groups

Security Levels50

User Security Privilege escalation attack Identity management Password protection Social engineering

Pretexting

Security Levels51

User Security User resistance New technologies

Security token Procedural Security

Operational security Dumpster diving Paper shredders

Backup and Disaster Recovery

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Backup: copying data regularly Recovery: restore data & restarting the

sys. after an interruption Disaster recovery plan: backup &

recovery plan Backup and disaster recovery issues

usually are intertwined


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Backup Policies Backup policy: detailed instructions &

procedures Backup media

Rotation schedule Offsiting

Backup Types Full backup: All files that match your selection are

included into the backup Differential backup: Only those files will be included

which have been changed since the last FULL backup


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Backup Policies Backup Types

Incremental backup: Only those files will be included which have been changed since the last backup

Continuous backup: automatically saved of every changed made

RAID (Redundant array of independent disks) Fault tolerant

Retention periods: keep the backup for a certain period of time


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Business Continuity Issues Test plan Business continuity plan (BCP) Hot site Data replication Business insurance

System Obsolescence56

At some point every system becomes obsolete

Signs: The system’s maintenance history

indicates that adaptive and corrective maintenance is increasing steadily

Operational costs or execution times are increasing rapidly, and routine perfective maintenance does not reverse or slow the trend


Signs: A software package is available that

provides the same or additional services faster, better, and less expensively than the current system

New technology offers a way to perform the same or additional functions more efficiently

Maintenance changes or additions are difficult and expensive to perform


Signs: Users request significant new features

to support business requirements Systems operation and support continues

until a replacement system is installed At some point in a system’s operational

life, maintenance costs start to increase, users begin to ask for more features and capability, new systems requests are submitted, and the SDLC begins again

Future Challenges and Opportunities

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The only thing that is certain about the future is continuous change

Change itself is neither good nor bad — the real issue is how people and companies deal with the challenges and opportunities that are bound to occur


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Predictions The highest priorities will be the safety and

security of corporate operations, environmental concerns, and bottom-line TCO

Gartner, Inc. is a leading IT consulting firm that is famous for forecasting industry trends


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Predictions Gartner also predicted that by 2011, large

enterprises will require suppliers to certify their green credentials and sourcing policies

Author Randall Stross notes that the enormous amount of energy needed to drive cloud computing, including Google’s servers, has raised serious environmental concerns


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Strategic planning for IT professionals Working backwards from your long-term

goals, you can develop intermediate mile stones and begin to manage your career just as you would manage an IT project

Planning a career is not unlike planting a tree that takes several years to reach a certain height


63

IT Credentials and Certification Credentials Certification In addition to Microsoft, many other IT

industry leaders offer certification, including Cisco, Novell, Oracle, and Sun Microsystems

Chapter Summary64

Systems support and security covers the entire period from the implementation of an information system until the system no longer is used

A systems analyst’s primary involvement with an operational system is to manage and solve user support requests

A maintenance team consists of one or more systems analysts and programmers

Chapter Summary65

Systems analysts need the same talents and abilities for maintenance work as they use when developing a new system

Configuration management is necessary to handle maintenance requests

Security is a vital part of every computer system

Risk management creates a workable security policy

Chapter Summary66

All information systems eventually become obsolete

An IT professional should have a strategic career plan that includes long-term goals and intermediate milestones

An important element of a personal strategic plan is the acquisition of IT credentials and certifications that document specific knowledge and skills

chapter 9 system maintenance

Documents

user security

system changes

systems maintenance

system failurewhen

network security

application security

physical security

file security