RDS & Using Read Replicas Flashcards Preview

A Cloud Guru - AWS SysOps Administrator Associate (2019) > RDS & Using Read Replicas > Flashcards

Flashcards in RDS & Using Read Replicas Deck (35)
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1
Q

What are read replicas?

A

Read-only copies of your DB that allow you to scale out for performance.

2
Q

How can a read replica be created?

A
  1. Management console

2. CreateDBInstanceReadReplica API

3
Q

Can you have a read replica of a read replica?

A

Yes, but there may be latency.

4
Q

Would you use a read replica to scale beyond your primary DB’s capacity?

A

Yes

5
Q

Would you use a read replica to serve traffic while the primary DB is unavailable?

A

Yes

6
Q

True or False: When running business reports, and performing data warehousing operations, it is best practice to use your primary DB instance?

A

False. Utilize read replicas for data-intensive workloads so the application is not affected.

7
Q

True or false: You could also import your data into RedShift for data warehousing operations to prevent load on the application DB?

A

True.

8
Q

Read replicas are supported on which non-Aurora databases?

A

MySQL
PostgreSQL
MariaDB

9
Q

True or False: Amazon uses a proprietary replication engine for read-replicas?

A

False. Amazon uses the native replication engines built into their supported DBs for read-replicas.

10
Q

True or False: Aurora uses SSD-Backed virtualized storage layer built for database workloads?

A

True

11
Q

What does AWS do when a read replica is created?

A

Takes a snapshot of your DB

12
Q

When creating a read replica, if multi-AZ is not enabled, what will the snapshot be of?

A

The primary DB.

13
Q

True or False: When a snapshot is made of the primary DB, there is a suspension of I/O for 1 minute?

A

True

14
Q

When creating a read replica, if multi-AZ is enabled, what will the snapshot be of?

A

Of the secondary database

15
Q

True or False: When a snapshot is made of the secondary DB, there is a suspension of I/O for 30 seconds?

A

False. Since the snapshot is not being made of the primary (production) DB, there is no I/O suspension

16
Q

True or False: Read replicas are accessed from the DNS of the primary DB?

A

False. You are given a new end point.

17
Q

True or false: Read replicas are a new end point, different from the primary and secondary DB (If multi-AZ is enabled)

A

True.

18
Q

Can you promote a read replica to be its own standalone DB?

A

Yes

19
Q

What will happen to the primary and secondary DB if a read replica is promoted?

A

replication will break.

20
Q

Up to how many read replicas per DB are supported?

A

5

21
Q

True or False: You can have read replicas in different regions?

A

True

22
Q

Read replica replications are synchronous, or asynchronus?

A

asynchronous.

23
Q

Multi-AZ DB replications are synchronous, or asynchronus?

A

synchronous

24
Q

Can read replicas be built off Multi-AZ DB?

A

Yes, this saves on performance impact.

25
Q

Can read replicas be multi-AZ?

A

Yes. This is a new service.

26
Q

Can DB snapshots be taken of read replicas?

A

No. Must use Mult-AZ to offload snapshot I/O performance hit

27
Q

Can automated backups be taken of read replicas?

A

No. Must use Mult-AZ to offload I/O performance hit

28
Q

Key metric to look for in read replicas?

A

REPLICA LAG

29
Q

What is replica lag?

A

The replication latency. The amount of time it takes for a write to the primary DB to replicate to the read replica DB.

30
Q

What is the difference between read replica and Multi-AZ?

A
  1. Read replica is a read only copy of your primary DB and is used for performance and scalability.
  2. Multi-AZ is for fail over only, and does not provide performance increases.
31
Q

Can you create a read replica if DB backups are disabled?

A

No. Backups must be enabled to use read replicas.

32
Q

When applying a modification to a DB, what two options are available for when the changes should be made?

A
  1. During the maintenance window.

2. Apply Immediately.

33
Q

True or False: When immediately applying a modification, any modifications that are scheduled within the normal maintenance window will also be executed?

A

True. Be careful when applying changes immediately. If you’re making a modification that you don’t expect will cause downtime, you may have a scheduled task that does cause downtime, which may lead to unscheduled outages.

34
Q

True or false: A read replica instance type can be different from the primary DB

A

True.

35
Q

True or false. If the primary DB is gp1, the read replica must also be gp1?

A

False. You have the option of selecting gp1, io1, or magnetic.