running in the cloud. • A DB instance can contain multiple user-created databases • Amazon RDS supports access to databases using any compatible SQL client application • You can have up to 40 DB instances in an account with some limitations
memory capacity and network bandwidth of an RDS DB instance • Each instance class relates to an EC2 instance type • There is three types of instance classes • Standard (M instances) • Memory Optimised (X, R and Z instances) • Burstable Performance (T instances)
underlying storage • 3 types of storages • General Purpose SSD: cost e ff ective, for various workloads • Provisioned IOPS SSD: for I/O intensive workload • Magnetic
support for DB instances • In Multi-AZ, RDS automatically provisions and maintains a synchronous standby replica in a di ff erent AZ • Standby instances are not used to scale database read • DB instances using Multi-AZ can have increased write and commit latency due to synchronous replication
in case of disruption • Failover uses DNS to switch the primary and the standby replica • Failover times are typically 60–120 seconds • Developer should be cautious of DNS cache retention to avoid longer disruption
SQL server • On Oracle, there is two mode of read replica • Read-only: Default mode • Mounted: The replica doesn’t accept user connection • It is possible to promote a read replica to primary instance • For MySQL and MariaDB databases, it is possible to replicate a DB external to RDS
in transit • It is possible to rotate SSL/TLS certi fi cate for optimum protection • It is possible to encrypt data on RDS instance via AES-256 encryption • RDS integrates with AWS KMS for key management
a speci fi c point in time, creating a new DB instance • You can restore to any point within your backup retention period • RDS uploads transaction logs for DB instances to Amazon S3 every 5 minutes
PgBouncer, PgPool, ProxySql or HirakiCP • RDS Proxy is ideal in a serverless environment as it reduce the burden of connection management on the database • The price depends on the RDS instance type used by your database. The larger the database instance, the more you end up paying
Good fi rst step before migrating to RDS on AWS in heavy VMware utilisation scenario • Easy scaling of instances • Cloudwatch metrics • Automatic and manual backup of on-premises databases • Point-in-time recovery
No read replica in another region support • Works only for MySQL, PostgreSQL, SQL Server • No encryption at rest • No replication with external databases
of one primary AWS Region where your data is mastered, and up to fi ve read-only secondary AWS Regions • Aurora replicates data to the secondary AWS Regions using dedicated infrastructure, with latency typically under a second • Aurora global databases doesn’t support • Multi-master clusters • Serverless v1 • Backtracking (Fast Point-in-time recovery)
v1 DB cluster seamlessly scales up and down based on the load generated by your client application • When it does need to perform a scaling operation, Aurora Serverless v1 fi rst tries to identify a scaling point, a moment when no queries are being processed • Aurora Serverless might not be able to fi nd a scaling point for the following reasons: • Long-running queries • In-progress transactions • Temporary tables or table locks