Which Amazon RDS feature provisions a synchronous standby replica in a different Availability Zone and automatically fails over to it if the primary database instance becomes unavailable?
Easy · Choose one
Explanation
Answer: B. An Amazon RDS Multi-AZ deployment maintains a synchronously replicated standby in a different Availability Zone. If the primary fails or the Availability Zone becomes unavailable, RDS automatically fails over by pointing the database endpoint at the standby, usually without any application change beyond a reconnect.
A. Read replicas use asynchronous replication and are intended to scale read traffic. Promoting one is a manual action and can involve data loss because replication lags.
C. Automated backups enable point-in-time recovery. Restoring from a backup creates a new instance and takes time; it is not an automatic failover.
D. A snapshot is a manual point-in-time copy used to restore a new instance. It provides no automatic failover.
52
An e-commerce application on Amazon RDS is slowing down because a nightly reporting job runs heavy SELECT queries against the production database. The company wants to move that read traffic off the primary instance. What should it implement?
Intermediate · Choose one
Explanation
Answer: A. Read replicas are asynchronous copies of the source database that serve read-only traffic. Directing the reporting workload to a replica removes that load from the primary instance, which continues serving transactional traffic. Read replicas are the standard mechanism for scaling reads in Amazon RDS.
B. In a Multi-AZ DB instance deployment the single standby exists purely for failover and does not serve read traffic, so it cannot run the reporting queries. (The separate Multi-AZ DB cluster deployment does provide two readable standbys, but that is not what this option describes.)
C. Migrating to DynamoDB would require a full re-architecture and would not naturally support the ad hoc analytical SQL that a reporting job uses.
D. Backup retention controls how far back point-in-time recovery can go. It has no effect on query performance.
53
Which AWS database service is MySQL-compatible and PostgreSQL-compatible, delivers significantly higher throughput than the standard community engines, and automatically maintains six copies of the data across three Availability Zones?
Intermediate · Choose one
Explanation
Answer: C. Amazon Aurora is a MySQL-compatible and PostgreSQL-compatible relational database built for the cloud. AWS states it delivers up to six times the throughput of stock MySQL and up to six times the throughput of stock PostgreSQL on similar hardware, and its distributed, fault-tolerant storage layer replicates each 10 GB chunk of the volume six ways across three Availability Zones, with continuous backup to Amazon S3.
A. RDS for MariaDB runs the community engine on a conventional storage volume. It does not use the Aurora distributed storage architecture or its six-way replication.
B. Amazon Redshift is a columnar data warehouse for analytics workloads, not a transactional relational engine.
D. Amazon DocumentDB is a document database with MongoDB compatibility. It is not MySQL or PostgreSQL compatible.
54
A web application repeatedly issues the same expensive database query, and the database instance is under pressure. The company wants to add a managed in-memory caching layer that is compatible with open source engines such as Valkey, Memcached, or Redis OSS. Which service should it use?
Intermediate · Choose one
Explanation
Answer: B. Amazon ElastiCache is a fully managed in-memory caching service. It provides Valkey-, Memcached-, and Redis OSS-compatible engines and is commonly placed in front of a database so that repeated read queries are served from memory in microseconds to milliseconds, which reduces load on the database and improves application response times.
A. A faster EBS volume improves disk throughput for the database, but it still means the query runs against the database engine each time rather than being cached.
C. CloudFront caches HTTP responses at edge locations for end users. It does not cache internal database query results.
D. Amazon S3 is durable object storage. It is not an in-memory cache and would not deliver sub-millisecond query results.
55
An application built on Amazon DynamoDB experiences a read-heavy workload and needs response times measured in microseconds rather than milliseconds. Which fully managed option should be added?
Intermediate · Choose one
Explanation
Answer: C. Amazon DynamoDB Accelerator (DAX) is a fully managed, highly available in-memory cache purpose-built for DynamoDB. It sits in front of the table and delivers microsecond read latency for cached items, with an API-compatible client so application code changes are minimal.
A. Global Tables replicate a table across Regions for multi-Region access and resilience. Within a Region, read latency remains in the single-digit millisecond range.
B. An RDS read replica belongs to Amazon RDS and has no relationship to a DynamoDB table.
D. DynamoDB Streams captures an ordered record of item-level changes for downstream processing. It does not accelerate reads.
56
A company is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL and needs to both translate the database schema and stored procedures and move the data while the source database keeps serving users. Which TWO services should be used? (Choose TWO.)
Intermediate · Select 2 answers
Explanation
Answer: A and C. This is a heterogeneous migration because the source and target engines differ. The AWS Schema Conversion Tool converts the source schema, views, stored procedures, and functions to the target engine's format and reports the parts that need manual work. AWS DMS then migrates the data and supports ongoing replication, so the source database remains fully operational during the migration and cutover downtime is minimized.
B. AWS Glue DataBrew is a visual data preparation tool for cleaning and normalizing data for analytics. It is not a database migration tool.
D. AWS Application Discovery Service collects usage and configuration data from on-premises servers to help plan a migration. It informs planning; it neither converts a schema nor moves data.
E. Redshift Spectrum queries data in Amazon S3 from Amazon Redshift. It has no role in migrating an Oracle database.
57
Which statement correctly contrasts an Amazon RDS Multi-AZ deployment with an Amazon RDS read replica?
Hard · Choose one
Explanation
Answer: C. Multi-AZ is a high availability and durability feature: data is replicated synchronously to a standby in another Availability Zone, and RDS fails over automatically when the primary is impaired. Read replicas are a scalability feature: data is replicated asynchronously to one or more replicas that serve read-only queries, and promoting a replica is a manual operation.
A. Both features apply across Amazon RDS engines. Neither is exclusive to Aurora, and DynamoDB does not use RDS read replicas at all.
B. This reverses the two features. The standby in a standard Multi-AZ deployment does not serve reads, and read replica promotion is not automatic.
D. Read replicas replicate asynchronously, which is why they can lag behind the source, and they do not fail over automatically.
58
A global mobile application needs users in North America, Europe, and Asia to read and write to a DynamoDB table with local low latency, and it must keep operating if one Region becomes unavailable. Which DynamoDB feature meets this requirement?
Hard · Choose one
Explanation
Answer: B. DynamoDB Global Tables provide a fully managed, multi-Region, multi-active database. AWS replicates the table to the Regions you select, and applications can read and write in whichever Region is closest to the user. If one Region becomes unavailable, traffic can be served from the remaining replica Regions.
A. DAX is an in-memory cache that reduces read latency within a single Region. It provides no cross-Region replication or Regional failover.
C. On-demand capacity mode changes how throughput is billed and scaled. It does not place data in additional Regions.
D. Point-in-time recovery protects against accidental writes and deletes by allowing restores to a previous time. It is a backup feature, not a Regional availability feature.
59
A company runs a self-managed MongoDB cluster and wants to move to a fully managed AWS database. Its applications must keep working with their existing MongoDB drivers, queries, and tools without being rewritten. Which service should the company use?
Hard · Choose one
Explanation
Answer: D. Amazon DocumentDB is a fully managed document database service that is designed to be compatible with MongoDB workloads. Because it implements the MongoDB API, existing drivers, queries, and tools continue to work, so the migration does not require the applications to be rewritten. AWS manages the underlying hardware, patching, backups, and scaling.
A. Amazon DynamoDB is a managed NoSQL key-value and document database, but it uses its own API. Every query and driver call in the application would have to be rewritten.
B. Amazon Neptune is a graph database for highly connected data. It does not implement the MongoDB API or the document data model these applications use.
C. Amazon RDS for PostgreSQL is a relational engine. Moving to it would require redesigning the document data model into tables and rewriting the queries in SQL.
60
Which TWO statements about Amazon DynamoDB are TRUE? (Choose TWO.)
Hard · Select 2 answers
Explanation
Answer: A and B. DynamoDB is a serverless database that stores data redundantly across multiple Availability Zones in a Region by default, giving built-in high availability and durability. For throughput, it offers on-demand capacity mode, which scales automatically and charges per request, and provisioned capacity mode, in which you specify read and write capacity units and can apply auto scaling.
C. DynamoDB is a NoSQL key-value and document store. Access patterns are designed around partition and sort keys and secondary indexes, not ad hoc relational joins.
D. Multi-Availability Zone redundancy is automatic and cannot be turned off. There is no separate Multi-AZ setting to enable.
E. DynamoDB has no instances to size and no engine to patch. AWS handles all of the underlying infrastructure, which is a defining feature of a serverless database.