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Measure · ISO 27001 and other standards

Test failover

Test whether a critical service can use its planned alternative during a failure. Check the required function and the return to normal operation.

Accountable: IT service ownerReviewed

Reuse existing records

Use the existing operations or recovery plan. Add the scenario and result to its maintenance or change ticket and link existing monitoring data, rather than creating a separate testing process.

What to do

  1. 1

    Agree the failure and return procedure

    Choose a specific failure with operations and identify the function that must remain available. Use the existing maintenance procedure to agree timing, an abort condition, a return path and acceptable interruption and data loss.

  2. 2

    Check switchover and functionality

    Carry out the agreed failure under controlled conditions and measure when the function becomes usable through the alternative. Check a normal business operation and, for services that write data, any lost or duplicate data. Also check permissions and monitoring so that the same level of security is maintained during alternative operation.

  3. 3

    Restore normal operation and fix gaps

    Return to normal operation using the agreed procedure and check the function again. Record the result and discrepancies in the existing ticket and repeat the affected step after a fix.

Worked example

Customer portal example

The team tests the failure of one of two portal instances.

One instance fails
DecisionOperations stops the agreed instance and checks sign-in and a test transaction through the remaining instance.
EvidenceTimestamps and result in the existing maintenance ticket.

Record the result

  • Existing maintenance or change ticket with the scenario and result.
  • Related measurements and, where needed, the completed fix.

Common implementation mistakes

Both instances share a failure point

Include shared dependencies such as storage, power and sign-in.

Checking only green monitoring signals

Test the function the business team actually needs.

Reuse the implementation across requirements

The references below show which requirements the measure contributes to.

View controls and standards
  • A.8.14 · Redundanz von informationsverarbeitenden EinrichtungenGerman guide

    The failure test shows whether the redundant alternative keeps the required service available.

  • A.5.30 · IKT-Bereitschaft für Business ContinuityGerman guide

    Measured interruption and return to service show whether IT supports the agreed recovery.

  • TISAX · 5.2.8

    VDA ISA 6.0.3 · Partial overlap

    The test supports assessment of recovery and target times for critical services. Other continuity scenarios remain separate.

    Reference

  • NIS2 · Art. 21(2)(c), (f)

    EU 2022/2555 · Partial overlap

    For entities in scope, the test supports continuity and effectiveness assessment. It does not replace full risk management or national applicability assessment.

    Reference

Resources for your next step

Sources and further reading