Disaster Recovery

Disaster Recovery

Disaster Recovery

• Disaster recovery is a planned set of steps that can be implemented to restore critical functionality of a network after a disaster has taken the entire network down.

• Troubleshooting deals with single station and group problems.

• The key to disaster recovery is planning and documentation of that plan.

Disaster Recovery

• When designing a disaster recovery plan, an administrator should consider the ‘worst case scenario’ for that network.

• This kind of plan is to account for extremes, not relatively minor outages, failures and security breaches.

Disaster Recovery

Disaster can include:• Hacker attacks• Electric power failures• Natural disasters such as fire, flood or

earthquake• Mistakes in system administration• Acts of nature, e.g. cyclones• Viral infestation of essential servers• Terrorism

Disaster Recovery

• A related concept is business continuity which ensures that an organisation’s critical business process, including IT systems, can be maintained in the event of disaster.

Disaster Recovery

Why is Disaster Recovery Important?

Disaster Recovery

• When executed well, disaster recovery procedures save large sums of money.

• Disaster recovery can also improve the quality of human life, and it may even save lives.

Disaster Recovery

• The terrorist attacks of 11 September 2001 in the United States, for example, caused large scale network outages.

• Among the affected systems were some of the fibre-optic telecommunications services provided by Verizon.

• Besides the financial impact to Wall Street firms from lost data connectivity, the loss of voice contact with friends and family greatly affected many individuals on that day.

Disaster Recovery

Things to consider in a disaster recovery plan include:

• Detection of the outages and other disaster effects as quickly as possible

• Contact names and details of essential staff (networking, managerial and other staff)

• Notification of affect parties• Isolation of affected systems• Roles and responsibilities of all staff in the

recovery process

Disaster Recovery

Things to consider in a disaster recovery plan include:

• Details of where backups are kept off site, what backups have been kept of what machines and the last time backups were created

• Details of network topology• Consideration of your customers and

employees• Testing and modifying to keep current with the

changes in the business• Repair of the critical affect systems

Disaster Recovery

• Part of any major upgrade to a network must also have a recovery plan for how to get back to a working system if something goes wrong.

• It is necessary to know which parts of a business are essential for the running of the business and which sections can take a little longer to get back to normal.

• This helps to priorities elements of the recovery plan.

Disaster Recovery

This type of plan may differ from the major recovery plan above but will still include such items as:

• Contact details for help, within or outside of the business - these contacts need to be advised of the upgrade and be available for a crisis

• Roles and responsibilities of all staff concerned• Details of backups

Disaster Recovery

Disaster Recovery Techniques

Disaster Recovery

All good IT disaster recovery plans consider the three main components of operations:

• Data• Systems• People

Disaster Recovery

• From the technical perspective, most organizations rely on some form of redundancy to make possible the recovery of data and systems.

• Redundancy allows secondary data or system resources to be passed into service at short notice should primary resources fail or otherwise become unavailable.

Disaster Recovery

• This concept is usually applied to hardware and it is now being increasingly applied to data.

• In other words, there must be more than one copy of data in existence at any one time.

Disaster Recovery

• Traditional backup strategies, for example, archive copies of critical data at a given point in time so that they can be restored later if needed.

• Organisations may also choose to replicate servers and other critical hardware at multiple locations to guard against any single point of failure.

Disaster Recovery

• While these and similar approaches have been a part of IT practice for many years, more sophisticated disaster recovery techniques have grown in popularity due to the terrorist events of 11 September 2001.

• Periodic data backups, for example, have limited value if the ‘snapshots’ are not taken frequently enough.

• Some organisations now generate so much data that even daily backups are too infrequent.

Disaster Recovery

• A more sophisticated approach like disk mirroring ensures that data remains available from multiple sources in near real-time.

• However, traditional mirroring only works over limited distances.

• Storage Area Network (SAN) and other competing technologies can alleviate this problem, albeit at a higher cost.

Disaster Recovery

• Another recent trend in IT disaster recovery planning - third party relocation services - gives organisations access to fully equipped operations space at temporary facilities in remote locations.

• These facilities can be a wonderful option in times of crisis ... if trained personnel are available to operate them.

Disaster Recovery

Facts and Figures

Disaster Recovery

In a 1998 Survey of 4, 255 IT Managers:• 59% had experienced financial loss due to

system downtime or failure during the last 12 months

• 55% had a disaster recovery plan• of this 55%, 34% had never tested the plan

Of the 440 businesses occupying the WTC and the thousands of surrounding businesses affected by lack of water and power, only approximately 200 gave evidence of any pre-planned continuity strategy.