RDS Multi-AZ Deployment

  • RDS Multi-AZ deployments provide high availability and automatic failover back up for DB instances
  • Multi-AZ helps improve the immovability and availability of a critical system, enhancing availability during planned system maintenance, DB example failure, and Availability Zone disruption.
  • RDS automatically creates a principal DB Instance and synchronously replicates the data to a standby example in a different AZ.
  • RDS performs an automatic failover to the standby, then that database operations tin be resumed as before long every bit the failover is complete.
  • RDS Multi-AZ deployment maintains the same endpoint for the DB Instance later on a failover, so the application tin can resume database operation without the need for manual administrative intervention.
  • Multi-AZ is a High Availability feature and Not a scaling solution for read-only scenarios; a standby replica tin can't be used to serve read traffic. To service read-only traffic, use a Read Replica.
  • Multi-AZ deployments for Oracle, PostgreSQL, MySQL, and MariaDB DB instances use Amazon engineering science, while SQL Server DB instances employ SQL Server Mirroring.
  • In a Multi-AZ deployment,
    • RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone.
    • Copies of information are stored in different AZs for greater levels of information durability.
    • Primary DB instance is synchronously replicated across Availability Zones to a standby replica to provide
      • data back-up,
      • eliminate I/O freezes during snapshots and backups
      • and minimize latency spikes during system backups.
    • DB instances may take increased write and commit latency compared to a Unmarried AZ deployment, due to the synchronous data replication
    • Transaction success is returned but if the commit is successful both on the primary and the standby DB
    • In that location might be a modify in latency if the deployment fails over to the standby replica, although AWS is engineered with low-latency network connectivity between Availability Zones.
  • When using the BYOL licensing model, a license for both the primary case and the standby replica is required
  • For product workloads, information technology is recommended to utilise Multi-AZ deployment with Provisioned IOPS and DB instance classes (m1.large and larger), optimized for Provisioned IOPS for fast, consistent performance.
  • When Unmarried-AZ deployment is modified to a Multi-AZ deployment (for engines other than SQL Server or Amazon Aurora)
    • RDS takes a snapshot of the master DB instance from the deployment and restores the snapshot into some other Availability Zone.
    • RDS then sets upwards synchronous replication betwixt the primary DB example and the new instance.
    • This avoids downtime during conversion from Single AZ to Multi-AZ.
  • An existing Single AZ instance tin exist converted into a Multi-AZ instance by modifying the DB instance without whatsoever reanimation.

RDS Multi-AZ Failover Procedure

  • In the event of a planned or unplanned outage of the DB instance,
    • RDS automatically switches to a standby replica in another AZ, if enabled for Multi-AZ.
    • The fourth dimension taken for the failover to complete depends on the database activity and other conditions at the fourth dimension the primary DB instance became unavailable.
    • Failover times are typically 60-120 secs. Still, large transactions or a lengthy recovery process can increment failover time.
    • Failover machinery automatically changes the DNS record of the DB instance to signal to the standby DB example.
    • Multi-AZ switch is seamless to the applications as in that location is no modify in the endpoint URLs but just needs to re-establish any existing connections to the DB example.
  • RDS handles failover automatically so that database operations can be resumed every bit apace every bit possible without administrative intervention.
  • Primary DB case switches over automatically to the standby replica if any of the following conditions occur:
    • Main Availability Zone outage
    • Loss of network connectivity to chief
    • Primary DB instance fails
    • DB instance'southward server blazon is inverse
    • Operating system of the DB case is undergoing software patching
    • Compute unit failure on the principal
    • Storage failure on the principal
    • A manual failover of the DB example was initiated using Reboot with failover (too referred to as Forced Failover)
  • If the Multi-AZ DB case has failed over, tin can be determined by
    • DB outcome subscriptions can be prepare to notify you via electronic mail or SMS that a failover has been initiated.
    • DB events can be viewed via the Amazon RDS console or APIs.
    • The current state of the Multi-AZ deployment tin can exist viewed via the RDS console and APIs.

AWS Certification Test Practice Questions

  • Questions are collected from Cyberspace and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • AWS test questions are not updated to go along upwardly the pace with AWS updates, so even if the underlying characteristic has changed the question might non be updated
  • Open to further feedback, give-and-take and correction.
  1. A company is deploying a new two-tier web application in AWS. The visitor has express staff and requires high availability, and the application requires complex queries and tabular array joins. Which configuration provides the solution for the company'south requirements?
    1. MySQL Installed on 2 Amazon EC2 Instances in a unmarried Availability Zone (does not provide High Availability out of the box)
    2. Amazon RDS for MySQL with Multi-AZ
    3. Amazon ElastiCache (Just a caching solution)
    4. Amazon DynamoDB (Not suitable for circuitous queries and joins)
  2. What would happen to an RDS (Relational Database Service) multi-Availability Zone deployment if the principal DB example fails?
    1. IP of the primary DB Instance is switched to the standby DB Instance.
    2. A new DB example is created in the standby availability zone.
    3. The canonical name record (CNAME) is changed from primary to standby.
    4. The RDS (Relational Database Service) DB instance reboots.
  3. Will my standby RDS instance be in the same Availability Zone as my chief?
    1. Simply for Oracle RDS types
    2. Yes
    3. Only if configured at launch
    4. No
  4. Is creating a Read Replica of another Read Replica supported?
    1. Just in sure regions
    2. Only with MySQL based RDS
    3. Only for Oracle RDS types
    4. No
  5. A user is planning to set up the Multi-AZ feature of RDS. Which of the below mentioned weather won't take advantage of the Multi-AZ characteristic?
    1. Availability zone outage
    2. A manual failover of the DB case using Reboot with failover option
    3. Region outage
    4. When the user changes the DB instance'due south server type
  6. When you run a DB Instance as a Multi-AZ deployment, the "_____" serves database writes and reads
    1. secondary
    2. backup
    3. stand by
    4. master
  7. When running my DB Instance every bit a Multi-AZ deployment, tin can I use the standby for read or write operations?
    1. Yeah
    2. Only with MSSQL based RDS
    3. Only for Oracle RDS instances
    4. No
  8. Read Replicas require a transactional storage engine and are only supported for the _________ storage engine
    1. OracleISAM
    2. MSSQLDB
    3. InnoDB
    4. MyISAM
  9. A user is configuring the Multi-AZ feature of an RDS DB. The user came to know that this RDS DB does not employ the AWS engineering, simply uses server mirroring to attain replication. Which DB is the user using right at present?
    1. MySQL
    2. Oracle
    3. MS SQL
    4. PostgreSQL
  10. If you have chosen Multi-AZ deployment, in the outcome of a planned or unplanned outage of your primary DB Example, Amazon RDS automatically switches to the standby replica. The automatic failover mechanism simply changes the ______ record of the main DB Instance to point to the standby DB Instance.
    1. DNAME
    2. CNAME
    3. TXT
    4. MX
  11. When automatic failover occurs, Amazon RDS volition emit a DB Instance event to inform yous that automatic failover occurred. You lot tin can use the _____ to return information about events related to your DB Instance
    1. FetchFailure
    2. DescriveFailure
    3. DescribeEvents
    4. FetchEvents
  12. The new DB Instance that is created when y'all promote a Read Replica retains the fill-in window menstruation.
    1. True
    2. Imitation
  13. Volition I be alerted when automatic failover occurs?
    1. Only if SNS configured
    2. No
    3. Yes
    4. Merely if Cloudwatch configured
  14. Can I initiate a "forced failover" for my MySQL Multi-AZ DB Instance deployment?
    1. Only in certain regions
    2. Only in VPC
    3. Yes
    4. No
  15. A user is accessing RDS from an awarding. The user has enabled the Multi-AZ feature with the MS SQL RDS DB. During a planned outage how will AWS ensure that a switch from DB to a standby replica will not affect admission to the application?
    1. RDS will have an internal IP which will redirect all requests to the new DB
    2. RDS uses DNS to switch over to standby replica for seamless transition
    3. The switch over changes Hardware so RDS does not demand to worry nigh access
    4. RDS will have both the DBs running independently and the user has to manually switch over
  16. Which of the following is part of the failover procedure for a Multi-AZ Amazon Relational Database Service (RDS) instance?
    1. The failed RDS DB instance reboots.
    2. The IP of the master DB instance is switched to the standby DB instance.
    3. The DNS record for the RDS endpoint is changed from primary to standby.
    4. A new DB instance is created in the standby availability zone.
  17. Which of these is non a reason a Multi-AZ RDS instance will failover?
    1. An Availability Zone outage
    2. A manual failover of the DB instance was initiated using Reboot with failover
    3. To autoscale to a higher example class (Refer link)
    4. Master database corruption occurs
    5. The primary DB case fails
  18. How does Amazon RDS multi Availability Zone model work?
    1. A second, standby database is deployed and maintained in a dissimilar availability zone from master, using synchronous replication. (Refer link)
    2. A second, standby database is deployed and maintained in a dissimilar availability zone from master using asynchronous replication.
    3. A second, standby database is deployed and maintained in a different region from chief using asynchronous replication.
    4. A 2nd, standby database is deployed and maintained in a different region from master using synchronous replication.
  19. A user is using a small MySQL RDS DB. The user is experiencing loftier latency due to the Multi AZ feature. Which of the below mentioned options may not help the user in this situation?
    1. Schedule the automatic back up in non-working hours
    2. Use a large or higher size case
    3. Utilize PIOPS
    4. Have a snapshot from standby Replica
  20. What is the accuse for the data transfer incurred in replicating information between your primary and standby?
    1. No accuse. It is free.
    2. Double the standard data transfer charge
    3. Aforementioned as the standard data transfer charge
    4. One-half of the standard data transfer charge
  21. A user has enabled the Multi AZ feature with the MS SQL RDS database server. Which of the below mentioned statements will help the user understand the Multi AZ feature better?
    1. In a Multi AZ, AWS runs two DBs in parallel and copies the data asynchronously to the replica re-create
    2. In a Multi AZ, AWS runs two DBs in parallel and copies the data synchronously to the replica copy
    3. In a Multi AZ, AWS runs just one DB but copies the information synchronously to the standby replica
    4. AWS MS SQL does not support the Multi AZ feature