- [Instructor] Disaster recovery plans are critical
to ensuring the continuity of business operations.
As with any security control,
disaster recovery plans should be tested
to ensure that the plan functions properly
and will be ready to restore business operations
in the event of a disruption.
Each test of a disaster recovery plan has two goals.
First, it validates that the plan functions correctly
and that disaster recovery technology will work
in the event of an actual disaster.
Second, the disaster recovery test provides
an opportunity to identify necessary updates to the plan
due to technology or business process changes.
Let's talk about five types of disaster recovery testing.
Read-throughs, walk-throughs,
simulations, parallel tests,
and full interruption tests.
Read-throughs are the simplest form
of disaster recovery testing.
They're also known as checklist reviews.
In this approach, disaster recovery staff distribute
copies of the current plan to all personnel involved
in disaster recovery efforts
and ask those personnel to review their procedures.
Team members then provide feedback about any updates needed
to keep the plan current.
Walk-throughs go a step further.
And involve getting everyone together around the same table
to review the plan.
For this reason, a walk-though
is also known as a tabletop exercise.
Walk-throughs achieve the same result as read-throughs
but are generally more effective
because they give the team the opportunity
to discuss the plan together.
The next level of disaster recovery testing
is the simulation test.
As with a structured walk-through,
simulations pull the disaster recovery team
together in the same room.
The difference is that in the simulation
they're not just talking about the plan itself.
They are discussing how they would respond
to a specific scenario.
The test planners design a simulation
of an emergency situation
and then the disaster recovery team
describes how they would react.
The three test types we've discussed so far
read-throughs, walk-throughs, and simulations
are all theoretical exercises.
They talk about disaster recovery
but don't actually use any disaster recovery technology.
The parallel test goes beyond this
and actually activates the disaster recovery plan.
Bringing up a hot or warm site
in response to a simulated disaster.
The company doesn't actually switch operations
to the alternate site,
but the alternate site runs in parallel
to the primary site.
The final test, the full interruption test,
is the most effective type of disaster recovery testing
but it is also the most disruptive to normal operations.
The business simulates a disaster by actually shutting down
the primary site and attempting to operate
out of the alternate facility.
This type of test will highlight
any deficiencies in the plan
but may also have an adverse effect on the business.
For this reason, full interruption tests
are rare in practice.
Disaster recovery testing strategies
often use a combination of different test types.
Organizations might conduct regular read-throughs
and walk-throughs of the plan,
and then supplement those walk-throughs and read-throughs
with periodic simulations and parallel tests.
Each test type brings different advantages
and helps the organization become better prepared
for an actual disaster.
At the conclusion of any disaster recovery test,
the team leader should prepare a written report
that summarizes the testing procedures
and the results of the test.
This report should also provide input from the team
on recommended changes to the plan
or recommended control improvements
that came up during the test.