AWS : Relational Database Service (RDS) - Basics Part 4

 ==============================================================
How do you maintain my database ? How can I plan for it?

• Any maintenance that causes downtime (typically only a few times per year) will be scheduled in your maintenance window
• Operating system or Amazon RDS software patches are usually performed without restarting databases
• Database engine upgrades require downtime
    • Minor version upgrades — automatic or manually applied (Automatic not applicable in case of SQL Server, always manual)
    • Major version upgrades — manually applied
    • Version deprecations—three-to six-month notification before scheduled upgrades
• View upcoming maintenanceevents in your AWS Personal Health Dashboard

==============================================================
How am I charged for Amazon RDS ?

• Database instance (instance hours)
    • Combination of Region + instance type + database engine + license (optional)
• Database storage (GB-mo)
    • Can be either provisioned (Amazon EBS) or consumed (Amazon Aurora)
    • Provisioned IOPS (IOPS-Mo) for IO1 storage type
    • Database I/O requests (IOs) for Amazon Aurora and Amazon EBS magnetic-storage types
• Backup storage (GB-mo
    • Size of backups and snapshots stored in Amazon S3
    • No charge for backup storage up to 100% of total database storage
• Data transfer (GB-mo)
    • Uses AWS regional data-transfer pricing

==============================================================
How can I save money on my database?

• Amazon RDS Reserved Instances (RIs) provide a discount over on-demand prices
• Region, instance family, and engine of on-demand usage must match to apply benefit
• Amazon RDS RIs offer size flexibility for open-source and Oracle BYOL engines
• By default, RIs are shared between allaccounts in consolidated billing
• Use the RI utilization report to determinehow your RIs are being used
    • Support for RI coverage reportcoming soon

==============================================================
Can I stop my database when it’s not in use?

• Stop and start a running database instance from the console or AWS CLI
• Available for single-AZ DB instances
• While instance is stopped, you only pay for storage
• Backup retention window is maintained while stopped
• Instances are restarted after 7 days
    • Pending maintenance operations are applied
    • Instances can be stopped again if desired

==============================================================

AWS : Relational Database Service (RDS) - Basics Part 3

 ==============================================================
How do I secure my Amazon RDS database?

• Amazon RDS is designed to be secure by default
• Network isolation with Amazon Virtual Private Cloud (Amazon VPC)
• AWS Identity and Access Management (IAM)-based resource-level permission controls
• Encryption at rest using AWS KMS (all engines) or Oracle/Microsoft TDE
• Use SSL protection for data in transit

==============================================================
What does Amazon VPC provide?

• Places your instance in a private subnet, making it secure from public routes on the Internet
• Database instance IP firewall protection lets you securely control network configuration
• Turn off Public Accessibility in DB instance settings to restrict access outside Amazon VPC
• Use ClassicLink to network with non-VPC resources

==============================================================
How do I grant access to my database?

• Use IAM to control who can perform actions on RDS resources
• Do not use AWS root credentials to manage Amazon RDS resources—you should create an IAM user for everyone, including yourself
• Can use AWS Multi-Factor Authentication (MFA) to provide extra level of protection

==============================================================
How do I encrypt my database?

- Use AWS KMS-based encryption in the AWS console
- No performance penalty for encrypting data
- Centralized access and audit of key activity
- Best practices
    • Encryption cannot be removed from DB instances
    • If source is encrypted, Read Replicas must be encrypted
    • Add encryption to an unencrypted DB instance by encrypting a snapshot copy

==============================================================
How do I monitor my Amazon RDS database ?

- Amazon CloudWatch metrics
    • CPU/Storage/Memory•Swap usage
    • I/O (read and write)
    • Latency (read and write)
    • Throughput (read and write)
    • Replica lag
- Amazon CloudWatch Alarms
    • Similar to on-premises monitoring tools
- Enhanced monitoring for Amazon RDS
    • Access to over 50 CPU, memory, file system, and disk I/O metrics
    • Low as 1-second intervals
-Integration with third-party monitoring tools

==============================================================
How do I improve database performance?

• Introducing Amazon RDS Performance Insights
• Measures DB Load: Average Active Sessions (AAS)
• Identifies database bottlenecks (Top SQL):
    • Easy
    • Powerful
• Identifies source of bottlenecks
• Enables problem discovery
• Adjustable time frame
    • Hour, day, week, and longer
• Coming soon for Amazon EBS-based Amazon RDS engines

==============================================================
Can I know when service events happen?

• Amazon RDS uses Amazon SNS to receive notification when an event occurs
• Notifications can be in any form supported by Amazon SNS (email, a text message, or a call to an HTTP endpoint)
• Six different source types (DB instance, DB parameter group, DB security group, DB snapshot, DB cluster, DB cluster snapshot)
• 17 different event categories (availability, backup, deletion, configuration change, etc.)

==============================================================

AWS : Relational Database Service (RDS) - Basics Part 2

 ==============================================================
How do I ensure database high availability?

• Multi-AZ provides enterprise-grade fault-tolerance solution for production databases
    • Automatic failover
    • Synchronous replication
    • Inexpensive and enabled with one click

==============================================================
What happens during a Multi-AZ failover? How long does it take?

• Each host manages set of Amazon EBS volumes with a full copy of the data
• Instances are monitored by an external observer to maintain consensus over quorum
• Failover initiated by automation or through the Amazon RDS API
• Redirection to the new primary instance is provided through DNS

==============================================================
Why would I use Read Replicas?

• Relieve pressure on your source database with additional read capacity
• Bring data close to your applications in different regions
• Promote a Read Replica to a master for faster recovery in the event of disaster
• Upgrade a Read Replica to a new engine version•Supported for MySQL, MariaDB, and PostgreSQL

==============================================================
When should I use Multi-AZ ?

 • Synchronous replication—highly durable
 • Only primary instance is active at any point in time
 • Backups can be taken from secondary
 • Always in two Availability Zones within a Region•Database engine version upgrades happen on primary
 • Automatic failover when a problem is detected

==============================================================
When should I use Read Replicas ?

 • Asynchronous replication—highly scalable
 • All replicas are active and can be used for read scaling
 • No backups configured by default•Can be within an Availability Zone, cross-AZ, or cross-region
 • Database engine version upgrades independently from source instance
 • Can be manually promoted to a standalone databaseRead ReplicasMulti-AZ

==============================================================
How does Amazon RDS manage backups?

• Two options –automated backups and manual snapshots
• Amazon RDS backups leverage Amazon EBS snapshots stored in Amazon S3
• Transaction logs are stored every 5 minutes in Amazon S3 to support point-in-time recovery (PITR)
• No performance penalty for backups
• Snapshots can be copied across regions or shared with other accounts

==============================================================
When should I use automated backups?

• Specify backup retention window per instance (7-day default)
• Kept until outside of window (35-day maximum) or instance is deleted
• Supports PITR
• Good for disaster recovery

==============================================================
When should I use snapshots?

• Manually created through AWS console, AWS CLI, or Amazon RDS API
• Kept until you delete them
• Restores to saved snapshot
• Use for checkpoint before making large changes, non-production/test environments, final copy before deleting a databaseManual snapshots

==============================================================
How do I restore a backup? Why does it take so long?

- Restoring creates an entirely new database instance
    • Define the instance configuration just like a new instance
    • Will get the default parameter, security, and option groups

- New volumes are hydrated from Amazon S3
    • While the volume is usable immediately, full performance requires the volume to warm up until fully instantiated
    • Migrate to a DB instance class with high I/O capacity
    • Maximize I/O during restore process

==============================================================

AWS : Relational Database Service (RDS) - Basics Part 1

==============================================================
What is Amazon RDS?

• Managed relational database service in the AWS cloud
• Multi-engine support: Amazon Aurora, MySQL, MariaDB, PostgreSQL, Oracle, SQL Server
• Automated provisioning, patching, scaling, replicas, backup/restore
• Easily scales to handle growth•High availability with Multi-AZ and Amazon Aurora

==============================================================

Why use Amazon RDS?

• Lower TCO because RDS manage “the muck”
    • Get more leverage from your teams
    • Focus on the things that differentiate you
• Built-in high availability and cross-region replication across multiple data centers
• Even a small startup can leverage multiple data centers to design highly available apps with over 99.95% availability

==============================================================
Which RDS engine should I use?

Amazon EBS-based Storage :
- Commercial : SQL Server and Oracle
- Open Source : MySQL , PostgreSQL and MariaDB
Aurora Storage System :
- AWS Cloud Native : MySQL CompatiblePostgreSQL Compatible

==============================================================
Which instance type should I choose?

- T2 Family
    • Burstable instances
    • 1 vCPU/1 GB RAM > 8  vCPU 32 GB RAM
    • Moderate networking performance
    • Good for smaller or variable workloads
    • Monitor CPU credit metrics in Amazon CloudWatch
    • T2.micro is eligible for free tier

- M3/M4 Family
    • General-purpose instances
    • 2 vCPU/8 GiB RAM > 64 vCPU 256 GiB RAM
    • High-performance networking
    • Good for running CPU intensive workloads (e.g., WordPress)

- R3/R4 Family
    • Memory-optimized instances
    • 2 vCPU/16 GiB RAM > 64 vCPU 488 GiB RAM
    • High-performance networking
    • Good for query-intensive workloads or high connection counts
==============================================================
Configuring DB Instance Class Processor ?

Modify processor features to optimize DB instance for specific workloads:
• Number of CPU Cores –Optimize licensing costs for instance with sufficient RAM for memory-intensive workloads, but fewer CPU cores
• Threads per Core –Disable Hyper-Threading for, e.g. HPC workloads

Changes can be applied when you:
• Create a DB instance
• Modify a DB instance
• Restore a DB instance from a snapshot
• Restore a DB instance to a point in time
==============================================================
Which AWS EBS storage type should I choose?

- General purpose (GP2)
    • SSD storage
    • Maximum of 16 TB
    • Leverages Amazon EBS Elastic Volumes
    • IOPS determined by volume size
    • Minimum of 100 IOPS (below 33.33GiB)
    • Bursts to 3,000 IOPS (applicable below 1.3 TB)
    • Baseline of 16,000 IOPS (at 3.3 TB and above)
    • Affordable performance

- Provisioned IOPS (IO1)
    • SSD storage•Maximum of 16 TB
    • Leverages Amazon EBS Elastic Volumes
    • Maximum of 40K IOPS (32K on SQL Server)
    • Delivers within 10% of the IOPS performance 99.9% of the time
    • High performance and consistency

- Magnetic
    • Magnetic storage
    • Maximum of 1 TB
    • Supported for legacy databases

- General purpose (GP3), is coming soon.
==============================================================
How do I decide between GP2 and IO1 AWS EBS Storage Type? Why am I not seeing less IOPS or only 30 K IOPS?

• GP2 is a great choice, but be aware of burst credits on volumes < 1 TB
    • Hitting credit-depletion results in IOPS drop—latency and queue depth metrics will spike until credits are replenished
    • Monitor BurstBalance to see percent of burst-bucket I/O credits available
    • Monitor read/write IOPS to see if average IOPS is greater than the baseline

==============================================================
How do I scale my database instance? Will there be downtime ?

• Scale compute/memory vertically up or down
    • Handle higher load to grow over time
    • Lower usage to control costs
    • New host is attached to existing storage with minimal downtime

• Scale up Amazon EBS storage (now up to 16 TB)
    • Amazon EBS engines now support Elastic Volumes for fast scaling (now including SQL Server)
    • No downtime for storage scaling
    • Initial scaling operation may take longer, because storage is reconfigured on older instances
    • Can re-provision IOPS on the fly

==============================================================