This content originally appeared on DEV Community and was authored by Le Huy Ho
Overview
RDS stands for Relational Database Service
It is a managed DB service for DB use SQL as a query language
-
It allows you to create databases in the cloud that are managed by AWS:
- Postgres
- MySQL
- MariaDB
- Oracle
- Microsoft SQL Server
- IBM DB2
- Aurora (AWS Proprietary database)
Advantage over using RDS vs deploying DB on EC2
-
RDS is a managed service:
- Automated provisioning, OS patching
- Continuous backups and restore to specific timestamp (point-in-time restore)
- Monitoring dashboards
- Read replicas for improved read performance
- Multi AZ setup for Disaster Recovery
- Maintenance windows for upgrades
- Scaling capability (vertical and horizontal)
- Storage backed by EBS
BUT you CAN NOT SSH into your instance
Storage Auto Scaling
Help you increase storage on your RDS DB instance dynamically
When RDS detects you are running out of free database storage, it scales automatically
Avoid manually scaling your database storage
You have to set Maximum Storage Threshold (maximum limit for DB storage)
-
Automatically modify storage if:
- Free storage less than 10% of allocated storage
- Low-storage lasts at least 5 minutes
- 6 hours have passed since last modification
Useful for applications with unpredictable workloads
RDS Read Replicas vs Multi AZ
RDS Read Replicas for read scalability
Up to 15 Read Replicas
Within AZ, Cross AZ or Cross Region
Replication is ASYNC, so reads are eventually consistent
Replicas can be promoted to their own DB
Application must update connection string to leverage read replicas
RDS Read Replicas - Use Cases
You have a production database that is taking on normal workload
You want to run a reporting application to run some analytics
You create a Read Replica to run the new workload there
The production application is unaffected
Read Replicas are used for SELECT (=read) only kind of statements (not INSERT, UPDATE, DELETE)
RDS Read Replicas - Network Cost
In AWS there is a network cost when data goes from one AZ to another
BUT For RDS Read Replicas within the same region, you don't pay that fee
RDS Multi AZ (Disaster Recovery)
SYNC replication
One DNS name - automatic app failover to standby
Increase availability
Failover in case of loss AZ, loss of network, instance or storage failure
No manual intervention in apps
Not used for scaling
*What I noted: *
Increase read workloads -> Read Replicas. Increase High Availability and disaster recovery -> Multi AZ
Read Replicas is ASYNC replication (read eventually consistent). Multi AZ is SYNC replication.
Read Replicas (manual). Multi AZ (automatically)
This content originally appeared on DEV Community and was authored by Le Huy Ho
Le Huy Ho | Sciencx (2024-10-21T14:14:07+00:00) Learning AWS – DVA – Day 10: Amazon RDS. Retrieved from https://www.scien.cx/2024/10/21/learning-aws-dva-day-10-amazon-rds/
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