Databases

Question 1

What are the 6 database types supported by AWS?

Answer 1

• Postgres
• Oracle
• MySQL
• MariaDB
• Microsoft SQL Server
• Aurora

Question 2

How many Read Replicas can you have?

Answer 2

5

Question 3

What is the consistency of the replication in Read Replicas?

Answer 3

It is ASYNC, so eventual consistency

Question 4

How do instances leverage a Read replica?

Answer 4

The update the connection string to connect to the Read Replica

Question 5

How do you enforce SSL in PostgreSQL or SQL Server?

Answer 5

On the AWS RDS Console in Parameter Groups, set rds.force_ssl=1

Question 6

How do you enforce SSL in MySQL or MariaDB?

Answer 6

In the DB, set:

GRANT USAGE ON . TO ‘mysqluser’@’%’ REQUIRE SLL;

Question 7

How many Read Replicas can Aurora have?

Answer 7

15

Question 8

What are 5 possible scenarios that would cause a RDS Failover in a Multi AZ setup?

Answer 8

• The primary DB instance fails
• An Availability Zone Outage
• The DB instance server type is changed
• Software patch of OS instance hosting the RDS instance
• A manual Reboot with Failover was initiated

Question 9

Does the RDS endpoint change of there is a failover?

Answer 9

No

Question 10

What 4 things do you not have access to in RDS, as it is managed by AWS?

Answer 10

• No SSH access
• No manual DB patching
• No manual OS patching
• No way to monitor underlying architecture

Question 11

What 7 Cloudwatch Metrics are collected by the RDS hypervisor?

Answer 11

• DatabaseConnections
• SwapUsage
• ReadIOPS / WriteIOPS
• ReadLatency / WriteLatency
• ReadThroughput / WriteThroughput
• DiskQueueDepth
• FreeStorageSpace

Question 12

What is RDS?

Answer 12

It is an in-memory key-value store used for cache

Question 13

What is Memcached?

Answer 13

It is an in-memory object store for cache