RDS Flashcards
This deck aims to help retain concepts related to the AWS RDS service.
What AWS service simplifies the relational database setup, operation, and scaling in the cloud?
Amazon Relational Database Service (RDS)
Can you access the operating system of RDS instances?
No, RDS is a managed service that does not provide access to the operating system or allow SSH access
Which database engines are supported by RDS?
Amazon Aurora, MySQL, MariaDB, PostgreSQL, Oracle, and Microsoft SQL Server
What type of replication is used when data is replicated to a standby instance?
Synchronous replication, ensuring that both the primary and standby instances have identical data
Where are RDS instances hosted?
RDS instances are hosted within a VPC in a specific AWS region, each instance has dedicated storage provided by EBS, and deployments can include multiple databases
Where are RDS backups stored?
Both automated backups and manual snapshots are stored in Amazon S3 (AWS-managed bucket)
Why is running and managing a database directly on an EC2 instance generally considered a bad practice?
- It involves significant administrative overhead and risk
- Managing backups and disaster recovery is complex
- EC2 and EBS are limited to a single availability zone
- Lacks advanced features and performance enhancements offered by AWS database products
- Does not support serverless options, easy scaling, or replication
What type of replication is used when data is replicated to a read replica, typically located in another region?
Asynchronous replication
What are the billing components of the RDS service?
- Instance size and type
- Multi-AZ deployment (additional instances)
- Monthly storage fee per GB
- Data transfer cost per GB (inbound and outbound from the internet or other AWS regions)
- Backup and snapshot storage per GB (snapshot storage is free up to the amount of provisioned storage, e.g., 2TB of storage equals 2TB of free snapshot storage)
- Licensing fees for commercial database engines (if applicable)
When might you consider running a database directly on an EC2 instance instead of using RDS?
- When access to the database instance’s operating system is required
- When advanced database tuning options are needed
- When the database engine or version is not supported by RDS
- When a specific OS or database combination that AWS does not provide is required
- When a particular architecture not supported by AWS is necessary (e.g., specific replication or resilience requirements)
- When there are vendor-specific requirements
- When decision-makers have a strong preference for direct control
What feature of RDS automatically creates a standby database instance, synchronously replicates data to it in a different availability zone, and provides automatic failover without manual intervention?
RDS Multi-AZ
What are the most common RDS Multi-AZ architectures?
- Instance Multi-AZ architecture (primary-secondary)
- Cluster Multi-AZ architecture (writer-reader-reader)
Based on the following characteristics, identify the Multi-AZ architecture:
- Synchronous data replication
- Only one standby replica
- Standby replica cannot be used for reads or writes until failover
- Failover takes 60-120 seconds (DNS update)
- Located in the same region (different AZ)
- Backups can be taken from the standby replica to improve performance
- Provides one endpoint that points to either the primary instance or the standby instance during failover
Instance Multi-AZ architecture (primary-secondary)
Based on the following characteristics, identify the Multi-AZ architecture:
- One writer synchronously replicates to readers in different AZs
- Two readers only
- Primary instance is used for write operations only
- Reader instances are used for read operations only
- Utilizes high-performance hardware (e.g., Graviton + local NVMe SSD storage)
- More efficient replication via transaction logs
- Writes are committed when at least one reader confirms replication
- Two endpoints provided:
- Cluster endpoint for primary instance (writer), used for reads, writes, and administration
- Reader endpoint for available readers, used for reads (may point to the primary instance for reads)
- Instance endpoints for specific instance access, generally for testing and troubleshooting
Cluster Multi-AZ architecture (writer-reader-reader)
What might trigger an RDS failover event?
- Availability Zone outage
- Primary instance failure
- Manual failover
- Instance type change
- Software patching
What backup and restore services are available within AWS RDS?
Automated Backups and Manual Snapshots
Based on the following characteristics, identify the RDS backup type:
- Automated, snapshots taken daily
- Retention period from 0 to 35 days
- Stores transaction logs every 5 minutes
- Can be deleted with RDS or retained until the expiration of the retention period
- Cross-region replication can be configured (not default)
- Allows recovery to any 5-minute point in time using the latest snapshots and transaction logs
Automated Backup
Based on the following characteristics, identify the RDS backup type:
- Not automatic
- Persist after RDS instance termination (must be manually deleted)
- Represents a single point in time
Manual Snapshot
Are automated backups or manual snapshots restored directly to the current RDS instance?
No, restoring from backups or snapshots creates a new RDS instance, resulting in a new database endpoint, and the restoration process can be slow
Which RDS feature allows the creation of one or more read-only copies of database instances within the same AWS region or across different regions to enhance scalability?
RDS Read Replica (improves global availability and resiliency)