Background

The database is down, so orders received from the shop cannot be processed immediately

Source

User

Stimulus

Sends an order to the shop

Reaction

The system detects the database is down and queues the order for 1 day. As soon as the database is back up, the queued orders are processed

Metric

If the database downtime is less than 1 day, the number of orders received must be equals to the number of orders queued.