RDS

Introduction

• Relational database service (RDS), including:

  • Amazon Aurora

  • PostgreSQL

  • MySQL

  • MariaDB

  • Oracle

  • Microsoft SQL Server.

Feature

• Storage with 10Gb per database in EBS (gp2 or io1)

• 2 copies of data in each AZ with minimum of 3 AZs (can choose AZ, and have 6 copies at least)

• Backups

  • Automated Backup

    • To recover database to any point in time in a retention period (5 minutes~35 days, 7 days as default).

    • Daily snapshots and transaction logs through the day (can do recovery down to a second)

    • Enabled by default, the backup takes the same size with DB and is saved on S3 freely

    • Will be deleted when DB is deleted

  • Snapshot

    • Manual operation, can copy cross region

    • Won't be deleted when DB is deleted

  • Additional support for Oracle

    • Oracle Export/Import Utilities

    • Oracle Data Pump Export and Import

    • Not support: Oracle Recovery Manager (RMAN), Replication Backups

• Encryption (for EBS, Snapshot)

  • Using AWS Key Management Service (KMS)

  • If a RDS is encrypted, its automated backups, read replicas, snapshots are encrypted as well

  • To encrypt an existing DB is not supported, instead create a new DB instance with encryption enabled then migrate data

• Disaster recovery with Multi-AZ deployments (synchronous replication for guarantee of durability)

  • supports:

    • PostgreSQL (physical replication)

    • MySQL (physical replication)

    • MariaDB (physical replication)

    • Oracle (physical replication)

    • SQL server (logical replication)

  • Have an exact copy of RDS in another AZ for automatic failover processing

  • DR for entire region down

    • Promote a read replica in a different region to stand alone DB (Single AZ).

    • Then reconfigure it as multi-AZ.

  • If being asked for data durability, still need to set up backups rather than only depending on multi-AZ.

• Read Replica (for scalability, it's eventual consistent)

  • Improve performance by using asynchronous replication from the primary RDS instance to the read replicas

  • Must have automatic backups turned on in order to deploy a read replica

  • Can have up to 5 replicas to any database

  • Can have replicas of read replicas

  • Can become an independent database but break the replication

  • Read replica supports Multi-AZ

  • Support for:

    • Aurora

    • PostgreSQL

    • MySQL

    • MariaDB

  • Read replica can be in another region

  • Read Replicas use automatic backups for managing read replica logs

    • To disable automatic backup, remove the read replicas first.

• Difference between Multi-AZ and Read Replicas in Amazon RDS

• To export RDS data to a MySQL instance running external to Amazon RDS

  • Prepare an external MySQL DB instance.

  • Prepare the source RDS MySQL DB instance for replication.

  • Use the mysqldump utility to transfer the database from the source MySQL DB instance to the external MySQL database.

  • Start replication to the external MySQL database.

  • After the export completes, stop replication.

• RDS maintenance

  • For updates marked as Required, You receive a notice from Amazon RDS indicating when the update will be performed, if you defer a required update.

  • For updates marked as Available, you can defer indefinitely.

• Transparent Data Encryption (TDE) are supported with Oracle, SQL Server.

• IAM Authentication for MySQL and PostgreSQL (authorization still happens inside RDS).

• Can copy an un-encrypted RDS snapshot into an encrypted one.

• CloudTrail cannot be used to track queries within RDS.

• Anti-patterns and suitable solutions

  • Lots of binary objects (S3)

  • Automated scalability, unstructured data, key-value data (DynamoDB)

  • Unsupport RDB types (Oracle DB2, SAP HANA), complete control of DB (EC2)

• Cross region failover

RDS Cross Region Failover

DynamoDB Scaling vs RDS Scaling

• DynamoDB offers a "push button" for easy scaling and leads no down time

• RDS needs manual operation to scale out (add replicas)/up (add instance size)

Amazon RDS on VMware database

• RDS in on-premises VMware environments.

• Migration to RDS by promoting RDS Read Replica, no need for DMS.