ASD ISM 1580 Ensure high availability for online services
What it says
Where a high availability requirement exists for online services, the services are architected to automatically transition between availability zones.
Quoted as published. Everything else on this page is written by Control Stack.
What it means
In plain EnglishOnline services should switch easily between zones to maintain availability.
This control ensures that your online business services stay available no matter what. If a problem happens in one area, the service can automatically switch to another area to keep running. This matters because if your online service goes down, you could lose customers, income, and trust.
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Why it matters
Without multi-zone automatic failover, a single availability zone outage can take the service offline, disrupting operations and potentially causing financial loss and reputational damage.
How to implement
System owners should work with IT personnel to determine the availability zones for the online services.
They can collaborate to understand which locations or cloud providers their services run from. This can be done with a map or list showing how services are set up to switch between zones.
IT teams should configure online services to automatically detect failures and switch to a backup zone.
They can do this by setting up software rules that monitor the server health and switch servers if a problem is found. This typically involves using cloud provider tools for automatic failover settings.
Managers responsible for business operations should ensure there's a service impact analysis plan.
This involves documenting what happens if your service goes offline and prioritising which services need high availability. They can gather key staff members for a planning session to develop this document.
Procurement teams must confirm that service agreements with cloud providers include high availability options.
Checking contract terms for dynamics like uptime guarantees and regional flexibility is essential. They can consult legal resources to ensure these terms are clear and enforceable.
IT leaders should organise regular testing of the failover mechanisms.
This could involve scheduled drills where the system is deliberately taken offline to observe if it correctly switches to a backup zone. These tests should be logged and reviewed to find any issues and ensure everything works as intended.
Keep it running
Regularly test automatic multi-zone failover to verify the service transitions between availability zones during a zone outage; record results and tune health checks, routing and deployment settings.
Evidence and audit
- Check 1 of 4What an auditor asks for
Ask for
The failover configuration documentation: Request written records or diagrams showing how services are set to automatically change zones.
Look at
Clearly labelled steps and zones outlined for each service.
Good evidence
Will have dated documents showing specific instructions and responsible parties for each step.
- Check 2 of 4What an auditor asks for
Ask for
A copy of the contract with cloud providers: Request agreements that cover high availability and failover capabilities.
Look at
The guaranteed uptime and response protocols sections.
Good evidence
Contract will clearly specify terms like '99.9% uptime' and procedures for when systems fail.
- Check 3 of 4What an auditor asks for
Ask for
The business impact analysis document: Request a document that sets out which services require high availability and potential impacts of downtime.
Look at
Assessments of impact severity and priority levels. A comprehensive document will list services, impact ratings, and responsible managers.
- Check 4 of 4What an auditor asks for
Ask for
A schedule of service checks and updates: Request evidence of regular reviews and updates to the system's resilience setup.
Look at
How often checks occur and if they're up to date.
Good evidence
Schedule will clearly document regular checks, responsible individuals, and any updates following checks.
Mappings
Closest match in ISO/IEC 27001: A.5.30, ICT readiness for business continuity, which this control partially meets.
ISO/IEC 27001: 3 mappings
This control partially meets A.5.30.
ISM-1580 requires that where high availability is needed for online services, those services are architected to automatically transition between availability zones. Annex A 5.30 requires organisations to plan, implement and test ICT readiness to meet business continuity and ICT continuity objectives, which commonly includes designing for failover and resilience. ISM-1580 is a specific architectural implementation pattern within the broader ICT continuity preparedness and testing expectations of Annex A 5.30.
This control partially meets A.8.14.
Annex A 8.14 requires information processing facilities to be implemented with redundancy sufficient to meet availability requirements. ISM-1580 is a specific application of this, requiring online services with a high availability requirement to be architected to transition automatically between availability zones. Annex A 8.14 applies to all information processing facilities, whereas ISM-1580 applies only to online services with high availability needs.
This control partially overlaps A.7.11.
ISM-1580 requires online services with high availability needs to automatically transition between availability zones to maintain service availability. Annex A 7.11 focuses on protecting information processing facilities from utility failures (e.g. power disruption), typically via redundant power and environmental support, which contributes to availability. They overlap on the availability objective, but ISM-1580 is about application/service zone failover architecture, while Annex A 7.11 is about facility/utility resilience rather than multi-zone service design.
Mappings show how controls relate across frameworks. They do not imply full equivalence or certification.