Quiz: AWS Storage: 20+ Questions!

Last verified: May 8, 2026. AWS limits and pricing change quickly.

What does the name S3 mean?

S3 stands for Simple Storage Service. It’s a scalable object storage service designed for large-scale data storage.

AWS S3 offers multiple storage classes:

• Standard: For frequently accessed data
• Infrequent Access (IA): Lower cost for less frequent access
• Glacier: Long-term, low-cost archival storage

Each class offers different pricing and access characteristics, allowing cost optimization based on data usage patterns.

Learn more about S3 Storage Classes

DynamoDB is considered “schema-less” because it allows you to store arbitrary properties in items without a predefined schema.

DynamoDB Best Practices

The key here is updates, not inserts or PUTs. If you’re doing inserts, you can use BatchWriteItem or TransactWriteItems.

While BatchWriteItem can handle multiple operations, it’s limited to PUTs and DELETES. TransactWriteItems is more powerful, but it’s a bit of a sledgehammer for simple updates. For simple updates, UpdateItem is the best choice. It allows you to UPDATE, or modify one or more attributes in an existing item.

The UpdateItem operation modifies one item per request. For large backfills or bulk updates, you typically orchestrate many UpdateItem calls or use a larger workflow such as PartiQL batch execution, Step Functions, Glue, EMR, or a custom worker process.

The UpdateItem operation:

• Updates an existing item’s attributes.
• Adds new attributes to an existing item.
• Removes attributes from an existing item.
• Conditionally performs the update if the item exists or meets certain conditions.

DynamoDB UpdateItem

OpenSearch is AWS’s managed service for search, log analytics, and full-text search workloads.

The distractors are useful services, but they are not the purpose-built search engine in this list:

• ElastiCache: Primarily an in-memory cache. Current ElastiCache for Valkey includes search commands for indexed in-memory data, so it is no longer accurate to describe the whole service as having no built-in search.
• Neptune: Graph database; it can integrate with OpenSearch for full-text search.
• Redshift: Data warehouse for SQL analytics.
• DocumentDB: Document database with MongoDB-compatible text search in supported versions.

Availability Zones (AZs) are distinct data centers within a region. RDS Multi-AZ deployment provides automatic failover to a standby replica in a nearby AZ.

Multi-AZ deployment:

• Provides automatic failover
• Increases database availability
• Creates a synchronous standby replica
• Minimizes downtime during infrastructure failures

Don’t confuse Multi-AZ deployment with Read Replicas, which are used for scaling read operations.

👋 I hope you’re having fun so far!

Time for a tricky one…

Which AWS service provides managed WebSocket APIs where AWS owns the client connection and routes messages to integrations?

API Gateway supports bidirectional WebSocket APIs, but the implementation is managed by API Gateway rather than being a direct socket into your own server process. API Gateway maintains the client connection and routes messages to Lambda, HTTP endpoints, or other integrations. Messages can be sent back to connected clients through the API Gateway Management API.

The others are much more WebSocket-friendly:

• Lightsail: Perfect for simple WebSocket setups 👌
• AppSync: Uses WebSockets for managed GraphQL subscriptions
• EC2: Your classic “do whatever you want” option for WebSockets
• EKS: Great for running scalable WebSocket clusters

Pro tip: If you need raw WebSocket power, stick with the compute services!

In virtually ALL systems, embracing a “least privilege” design is a key way to harden & future proof. Trying to lock down an existing system is about as difficult as moving an entire office building to a new foundation.

S3 buckets are no exception. To apply the principle of least privilege, start with no permissions and grant only the necessary access. Use IAM roles and policies to control access and regularly audit bucket permissions.

Security best practices:

• Apply least privilege principle
• Start with no permissions
• Grant only necessary access
• Use IAM roles and policies
• Regularly audit bucket permissions

Avoid overly permissive settings that could expose sensitive data.

S3 Security Best Practices

Aurora Serverless:

• Automatically scales compute capacity
• Adjusts resources based on workload
• Ideal for unpredictable workloads
• Pay only for used resources

Great for applications with variable traffic patterns.

Aurora Serverless Overview

The DynamoDB SDK allows you to retrieve up to 100 items in a single BatchGetItem request. This is higher than the limit for BatchWriteItem, which is 25 items. Additionally, there are limits on the total payload size, document size, and request rate.

Understanding these limits is crucial for optimizing your application’s performance and ensuring efficient data operations.

Note: It is possible to exceed some of these limits - if you can sweet-talk your AWS account manager. 😎

The DynamoDB Clients are essentially all wrappers for its HTTP API. The BatchWriteItem operation can PUT or DELETE up to 25 documents per HTTP request, but it cannot UPDATE multiple documents.

While DynamoDB can INSERT up to 25 documents per HTTP request, it can UPDATE only 1 document per request using the UpdateItem operation.

On-Demand Capacity is best for:

• Unpredictable workloads
• Sporadic traffic
• Applications with unknown access patterns
• Avoiding over-provisioning

Provisioned capacity is better for:

• Predictable, consistent workloads
• More control over performance
• Potential cost savings

DynamoDB Capacity Modes

S3 Performance Tips:

• Modern S3 automatically scales request rates per prefix
• You don’t need random/hash prefixes for performance
• Use logical key names that fit your access patterns
• Monitor 503 Slow Down responses if you push very high request rates

Old guidance recommended randomizing prefixes to avoid hot partitions, but AWS no longer recommends that as a default performance requirement.

S3 Performance Guidelines

Best Backup Practices:

• Enable automated backups
• Use point-in-time recovery
• Retain backups based on compliance needs
• Test restoration process regularly
• Consider cross-region backup

Automated backups provide:

• Continuous data protection
• Flexible recovery options

RDS Backup Best Practices

Redis Advantages:

• Supports complex data structures
• Persistence options
• Advanced operations
• Pub/Sub messaging

Memcached:

• Simple key-value store
• Pure caching
• High performance for simple use cases

Redis vs Memcached

Global Secondary Index (GSI):

• Allows querying on non-primary key attributes
• Creates alternative access patterns
• Increases query flexibility
• Comes with additional write capacity cost

Useful for complex query requirements beyond primary key.

DynamoDB Indexes

Lifecycle Management:

• Automatically transition objects between storage classes
• Move infrequent data to cheaper storage
• Set rules for object expiration
• Optimize storage costs
• Reduce manual management overhead

S3 Lifecycle Rules

Amazon Aurora supports up to 15 read replicas, allowing you to significantly scale your read operations. These replicas benefit from:

• Near-instantaneous replication across replicas
• Minimal performance impact on the primary instance
• Efficient distribution of read workloads

This setup enables horizontal scaling for applications with heavy read demands.

Learn more about Aurora Read Replicas

RDS Encryption Features:

• Encrypt data at rest using KMS
• Encrypt data in transit using SSL/TLS
• Enable encryption during database creation
• Protect sensitive information
• Compliance with security standards

RDS Encryption Options

DynamoDB Streams:

• Capture item-level changes
• Enable event-driven architectures
• Trigger Lambda functions
• Support cross-region replication
• Provide near real-time data movement

DynamoDB Streams Overview

Multipart Upload Benefits:

• Handle large files efficiently
• Resume interrupted uploads
• Parallel upload of file parts
• Recommended for files > 100MB
• Improved network reliability

S3 Multipart Upload

Optimal Storage Strategy:

• 20% in S3 Standard for daily access
• 30% in S3 Standard-IA for monthly access
• 50% in Glacier for yearly access

This approach optimizes costs while maintaining appropriate access patterns.

Cost Considerations:

• Storage pricing per GB
• Retrieval costs
• Access patterns
• Transition costs

Understanding DynamoDB consistency models is crucial:

• 1 RCU = 1 strongly consistent read/second for items up to 4KB
• 1 RCU = 2 eventually consistent reads/second for items up to 4KB

Therefore:

• 100 RCUs = 100 strongly consistent 4KB reads/second
• 100 RCUs = 200 eventually consistent 4KB reads/second

Choose consistency models based on:

• Application requirements
• Cost considerations
• Performance needs
• Data freshness requirements

Aurora Failover Process:

1. Detects primary instance failure
2. Chooses an Aurora Replica based primarily on failover priority tier
3. Uses instance characteristics as tie-breakers when priorities match
4. Updates cluster endpoint automatically

Best Practices:

• Maintain multiple replicas across AZs
• Configure promotion tiers intentionally
• Use cluster endpoint in applications
• Test failover scenarios regularly

S3 Consistency Model:

• Strong read-after-write consistency for all operations
• Applies to PUTs and DELETEs
• No need for workarounds previously used
• No additional cost

Impact:

• Simplified application logic
• No need for consistency checks
• Reliable immediate reads after writes
• Improved application reliability

DynamoDB TTL Characteristics:

• Background process monitors TTL attribute
• Expired items are deleted on a best-effort schedule, typically within a few days
• No additional cost for TTL
• Deleted items appear in streams

Use Cases:

• Session management
• Log expiration
• Temporary data cleanup
• Regulatory compliance

Aurora Serverless Scaling:

• Aurora Serverless v2 scales capacity in fine-grained ACU increments
• Scaling speed depends on current capacity and min/max ACU settings
• Supported versions can auto-pause at 0 ACUs when configured
• Billing per-second based on ACUs

Best Practices:

• Set minimum capacity high enough for sudden spikes on critical workloads
• Monitor scaling events
• Keep connection management in mind