Amazon RDS

Amazon RDS – Relation Database service providers you easily setup, operate, scalable relation database on cloud. It has many features and benefits terms of close database.

RDS Overview

  • Its manage service and you can not access environment directly.
  • CPU, memory, storage, and IOPS can be scaled independently.
  • manages backups, software patching, automatic failure detection, and recovery.
  • supports MySQL, MariaDB, PostgreSQL, Oracle, Microsoft SQL Server, and the new, MySQL-compatible Amazon Aurora DB engine
  • manages backups, software patching, automatic failure detection, and recovery.
  • Read Replicas to increase read scaling for MySQL, MariaDB, or PostgreSQL

DB Instance

  • basic fundamental term in RDS.
  • for each DB instance, 5 GB to 6 TB of associated storage capacity can be selected
  • storage comes in three types: Magnetic, General Purpose (SSD), and Provisioned IOPS (SSD), which differ in performance characteristics and price

Regions and Availability Zones

  • DB instances can be hosted in several AZs, an option called a Multi-AZ deployment.

Security Groups

  • security group controls the access to a DB instance, by allowing access to the specified IP address ranges or EC2 instances

DB Parameter Groups

  • A DB parameter group contains engine configuration values that can be applied to one or more DB instances of the same instance type

DB Option Groups

  • Some DB engines offer tools that simplify managing the databases and making the best use of data.

RDS Pricing

Pricing is depend on below criterias

  • Instance class
  • Running time
  • Storage
  • I/O requests per month
  • Backup storage
  • Data transfer
  • Reserved Instance

RDS Storage

  • RDS storage uses Elastic Block Store (EBS) volumes for database and log storage.
  • RDS automatically stripes across multiple EBS volumes to enhance IOPS performance, depending on the amount of storage requested

RDS Multi-AZ & Read Replica Overview

There are two way of making replicas in RDS – Multi-AZ and Read Replica.

Multi-AZ deployment

  • Multi-AZ deployment provides high availability and failover support
  • RDS automatically provisions and manages a synchronous standby replica in a different AZ (independent infrastructure in a physically separate location)
  • RDS automatically fails over to the standby so that database operations can resume quickly without administrative intervention in case of
    • Planned database maintenance
    • Software patching
    • Rebooting of the Primary instance
    • Primary DB instance connectivity or host failure, or an
    • Availability Zone failure

Read Replica

  • RDS uses the PostgreSQL, MySQL, and MariaDB DB engines’ built-in replication functionality to create a special type of DB instance called a Read Replica from a source DB instance.
  • Load on the source DB instance can be reduced by routing read queries from applications to the Read Replica.
  • Read Replicas allow elastic scaling beyond the capacity constraints of a single DB instance for read-heavy database workloads

RDS snapshot, Backup & Restore Overview

  • RDS creates a storage volume snapshot of the DB instance, backing up the entire DB instance and not just individual databases.
  • RDS provides two different methods Automated and Manual for backing up your DB instances:

Automated backups

  • Backups of the DB instance are automatically created and retained
  • Automated backups are enabled by default for a new DB instance.
  • Automated backup occurs during a daily user-configurable period of time, known as preferred backup window.
  • Backups created during the backup window are retained for a user-configurable number of days , known as backup retention period
  • During the backup window,for Single AZ instance, storage I/O may be briefly suspended while the backup process initializes (typically under a few seconds) and a brief period of elevated latency might be experienced.
  • for Multi-AZ DB deployments, there is No I/O suspension since the backup is taken from the standby instance
  • Automated DB snapshots are deleted when
    • the retention period expires
    • the automated DB snapshots for a DB instance is disabled
    • the DB instance is deleted
  • When a DB instance is deleted,
    • a final DB snapshot can be created upon deletion; which can be used to restore the deleted DB instance at a later date.
    • RDS retains the final user-created DB snapshot along with all other manually created DB snapshots
    • all automated backups are deleted and cannot be recovered

Manual Backup

  • Manual DB snapshots are user-initiated backups that enables to back up a  DB instance to a known state, and restore to that specific state at any time.
  • RDS keeps all manual DB snapshots until explicitly deleted

Point-In-Time Recovery

In addition to the daily automated backup, RDS archives database change logs. This enables recovery of the database to any point in time during the backup retention period, up to the last five minutes of database usage.

DB Snapshot Sharing

Manual DB snapshot or DB cluster snapshot can be shared with up to 20 other AWS accounts.

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