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?
A.
In a Multi AZ, AWS runs two DBs in parallel and copies the data asynchronously to the replica copy
B.
In a Multi AZ, AWS runs two DBs in parallel and copies the data synchronously to the replica copy
C.
In a Multi AZ, AWS runs just one DB but copies the data synchronously to the standby replica
D.
AWS MS SQL does not support the Multi AZ feature
Explanation:
Amazon RDS provides high availability and failover support for DB instances using Multi-AZ deployments. In a
Multi-AZ deployment, Amazon RDS automatically provisions and maintains a synchronous standby replica in a
different Availability Zone. The primary DB instance is synchronously replicated across Availability Zones to a
standby replica to provide data redundancy, eliminate I/O freezes, and minimize latency spikes during system
backups. Running a DB instance with high availability can enhance availability during planned system
maintenance, and help protect your databases against DB instance failure and Availability Zone
disruption.Note that the high-availability feature is not a scaling solution for read-only scenarios; you cannot
use a standby replica to serve read traffic. To service read-only traffic, you should use a read replica.
When you provision a Multi-AZ DB Instance, Amazon RDS automatically creates a primary DB Instance and synchronously replicates the data to a standby instance in a different Availability Zone (AZ)
B.
In a Multi AZ, AWS runs two DBs in parallel and copies the data synchronously to the replica copy
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C is correct.
primary DB and standby DB is NOT parallel.
Amazon RDS automatically provisions and maintains a synchronous “standby replica” in a different Availability Zone.
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Answer is C:
Amazon RDS for Microsoft SQL Server
https://aws.amazon.com/rds/sqlserver/
“Multi-AZ Deployments – When you create or modify your DB Instance to run as a Multi-AZ deployment, Amazon RDS will automatically provision a primary database in one Availability Zone and maintain a synchronous “standby” replica in a different Availability Zone.”
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Looks like this is a B vs. C discussion and I am going to cast my vote for B because the standby is indeed a running instance. The replica DB is not accepting connections from a web server but it is accepting data from the primary instance and actually propagating it to the tables to be ready to take on the job if neeed. Its kind of like the Vice President – awake, alert and ready to take charge if needed even though he isn’t actually seated in the Oval Office.
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Answer is C:
See. http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html
“The primary DB instance is synchronously replicated across Availability Zones to a standby replica”
There is no mention of parallels DBs
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Hi, guys, I choose D, for RDS do not support the MS SQL Server Multi-AZ, if you want to deploy it multi-az, choose EC2 to deploy.
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C
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The answer should be C.
High availability does not mean that Amazon keeps, for example, two databases running in parallel; it is the data on disk that is replicated. If the primary DB instance becomes unavailable, a failover begins and the database software is started on the standby replica. The time it takes for the failover to complete depends on the database activity and other conditions at the time the primary DB instance became unavailable. When the failover is complete, it can take additional time for the RDS console UI to reflect the new Availability Zone.
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C
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c
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C
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Hmmm, i think the question is wrong. The “standby” replica is up, so actually 2 DB instances are running in parallel … but they are not accessed in parallel.
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http://docs.aws.amazon.com/zh_cn/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html
C
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C
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