Redundancy and failover design in SCADA systems - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is redundancy in the context of SCADA systems?

Redundancy means having extra components or systems ready to take over if the main ones fail, so the SCADA system keeps working without interruption.

beginner

Explain failover in simple terms.

Failover is the automatic switch to a backup system when the main system stops working, like having a spare tire ready when your car's tire goes flat.

intermediate

Why is redundancy important in SCADA systems?

Because SCADA controls critical processes, redundancy helps avoid downtime and keeps operations safe and reliable even if parts fail.

intermediate

Name two common types of redundancy used in SCADA systems.

1. Hardware redundancy: duplicate physical devices like servers or controllers. 2. Network redundancy: multiple communication paths to avoid single points of failure.

advanced

What is the difference between active-active and active-passive failover?

Active-active means all systems run at the same time sharing the load, so if one fails, others keep working. Active-passive means one system runs while the backup waits to take over if needed.

What does redundancy in SCADA systems help prevent?

A User errors

B Faster processing

C System downtime

D Data encryption

Redundancy helps prevent system downtime by having backup components ready.

Which failover type involves a backup system running only when the main system fails?

A Active-passive

B Load balancing

C Active-active

D Failback

Active-passive failover means the backup system is passive until needed.

In SCADA, what is network redundancy?

A Backup software licenses

B Multiple communication paths

C Duplicate sensors

D Extra power supplies

Network redundancy means having multiple communication paths to avoid failure.

Failover is best described as:

A Data backup

B Manual system restart

C System shutdown

D Automatic switch to backup

Failover automatically switches to a backup system when the main one fails.

Why is redundancy critical in SCADA systems?

A To ensure continuous operation

B To reduce costs

C To improve user interface

D To increase data storage

Redundancy ensures continuous operation by preventing downtime.

Describe how redundancy and failover work together to keep SCADA systems reliable.

Think about having spare parts and a plan to use them when needed.

List and explain two types of redundancy used in SCADA systems and why each is important.

Consider physical devices and communication lines.