Create a smart electric meter software system for an apartment complex that includes one dashboard for tenants, displaying hourly, weekly, monthly, and yearly readings specific to their units. Additionally, provide another dashboard for the building owner that presents similar readings, but categorized by floors or overall building electricity consumption.

The interviewer is assessing your comprehension of designing and implementing a large-scale software system, particularly for the control and monitoring of electricity consumption. Your design should address the varying requirements of different user roles (tenants and owners). Tenants require a detailed report of their individual consumption, whereas the owner needs a broader summary of electricity usage per floor or for the entire building. Additionally, you should consider factors such as efficiency, scalability, and reliability, as well as how your design will manage various time frames (hourly, weekly, monthly, yearly). As you respond to this question, you should consider the following points: Identification of different users and their requirements. Implementation and architectural decisions. Scalability and system optimization. Consideration of time frames.

When developing a smart electric meter software system for this apartment building, it is essential that our system can accurately and efficiently monitor and report usage data. To achieve this, I recommend implementing a microservice architecture, which will be advantageous for scalability and the manageability of individual services. I would organize the architecture into five primary services: Authentication Service : This service verifies the identities of tenants and owners and determines the information they are permitted to access. Tenant Service : This service collects and displays detailed reports of usage statistics for each tenant's unit on an hourly, weekly, monthly, and yearly basis. Owner Service : This service provides the owner with data on a per-floor or entire building basis, also across various time frames. Meter Reading Service : This service is responsible for collecting meter data, processing it, organizing it by time and corresponding units, and forwarding it to the Tenant and Owner services. Database Service : This service acts as a central repository for all energy usage data, which can be accessed by other services for real-time updates. By utilizing the Apache Kafka streaming platform, we can ensure the efficient, high-speed transfer of data from the Meter Reading Service to the other services. We will employ a time-series database to archive all readings, allowing us to easily retrieve both historical and real-time data. To ensure the system can accommodate growing data volumes, we may want to consider sharding our database based on building floors or individual units as traffic and data volume increase.

To create a software system for smart electric meters, I recommend a three-tier architecture consisting of a presentation layer, a business logic layer, and a data layer. Within the presentation layer , we should develop two distinct interfaces. One will cater to tenants, showing usage data related to their specific units over various timeframes. The other will be for the building owner, displaying electricity usage data by floor or for the entire building. The business logic layer will consist of multiple servers to manage user requests. We will require one server to handle tenant requests, which retrieves and provides electricity usage information for individual apartments. Additionally, another server will be necessary for the owner's requests, which will gather and present data by floor or for the building as a whole, according to the owner's specifications. In the data layer , it is essential to have a well-structured database that captures all electric meter readings for each apartment, with timestamps to facilitate data retrieval over different time periods. To ensure scalability, the software system should be architected to allow the addition of new servers in the business logic layer as user requests increase. To manage growing data volumes, we may implement data partitioning in the databases. To maintain continuous uptime and enhance fault tolerance, we can utilize strategies such as data replication and deploying redundant servers. This system will meet the needs of both tenants and the owner, providing a solution that is scalable, resilient, and capable of managing large data volumes.