KindleYou Replication Issues
Question
KindleYou is a location-based social search mobile app that allows users to like or dislike other users, and allows users to chat if both parties liked each other in the app.
It has more than 1 billion customers across the world. They use DynamoDB to support the mobile application and S3 to host the images and other documents shared between users.
KindleYou has a large customer base spread across multiple geographic areas.
Customers need to update their profile information while using the application. Team understands the Global tables are the right solution to implement replication.
The solution is implemented in 2 additional replica copies.
CloudWatch is used to monitor the global tables.
Over time, the team identifies the following issues: a)Updates from one replica are not propagating to other replica tables in a timely manner. b)The number of item updates that are written to one replica table, but that have not yet been written to another replica in the global table Why do you think so and what metrics and action can help resolve the issues? select 3 options.
Answers
Explanations
Click on the arrows to vote for the correct answer
A. B. C. D. E. F.Answer:A, C,F.
Option A is correct - ReplicationLatency and PendingReplicationCount metrics provide the information about the monitoring and performance of replica of the global tables using cloudwatch.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_monitoringhtml.
Option B is incorrect -ReplicationLatency and PendingReplicationCount metrics provide the information about the monitoring and performance of replica of the global tables.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_monitoringhtml.
Option C is correct - Verify whether the read capacity units (RCUs) and write capacity units (WCUs) are identical for each of the replica tables.
In addition, the WCU settings you choose should follow the recommendations in Best Practices and Requirements for Managing Capacity.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_monitoringhtml.
Option D is incorrect -there is no metric called ReplicationCount.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_monitoringhtml.
Option E is incorrect -there is no metric called PendingReplicationLatency.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_monitoringhtml.
Option F is correct - verify that the provisioned write capacity settings are sufficient for your current workload.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_monitoringhtml.
The issues identified in the scenario are related to the replication of data across the global tables. Specifically, updates from one replica table are not propagating to other replica tables in a timely manner, and there is a high number of item updates that are written to one replica table but not yet written to another replica in the global table. To address these issues, we can use metrics and take specific actions.
A. ReplicationLatency and PendingReplicationCount metrics provide information about the issue
- ReplicationLatency: measures the time taken for updates to propagate from the source replica to all the other replica tables in the global table.
- PendingReplicationCount: measures the number of updates that are written to one replica table but have not yet been written to another replica in the global table.
- By monitoring these metrics, we can identify if there is a delay in replication and how many updates are pending replication.
C. To resolve ReplicationLatency, verify that the read capacity units (RCUs) and write capacity units (WCUs) are identical for each of the replica tables.
- The RCUs and WCUs determine the amount of throughput provisioned for each replica table.
- If the throughput is not the same across all replica tables, it may cause replication delays.
- By ensuring that the RCUs and WCUs are the same for all replica tables, we can improve replication performance.
D. To resolve ReplicationCount, verify that the provisioned write capacity settings are sufficient for your current workload.
- The provisioned write capacity determines the number of writes that can be processed per second for each replica table.
- If the provisioned write capacity is not sufficient for the workload, it may cause a backlog of pending updates and replication delays.
- By increasing the provisioned write capacity, we can reduce the backlog and improve replication performance.
F. To resolve PendingReplicationCount, verify that the provisioned write capacity settings are sufficient for your current workload.
- As mentioned earlier, the provisioned write capacity determines the number of writes that can be processed per second for each replica table.
- If the provisioned write capacity is not sufficient for the workload, it may cause a backlog of pending updates.
- By increasing the provisioned write capacity, we can reduce the backlog and improve replication performance.
E. To resolve PendingReplicationLatency, verify that the read capacity units (RCUs) and write capacity units (WCUs) are identical for each of the replica tables.
- Similar to resolving ReplicationLatency, ensuring that the RCUs and WCUs are the same for all replica tables can improve replication performance and reduce the backlog of pending updates.
In summary, to resolve the issues identified in the scenario, we can monitor the ReplicationLatency and PendingReplicationCount metrics, ensure that the RCUs and WCUs are the same for all replica tables, and increase the provisioned write capacity if it is not sufficient for the workload.
