Analysis

Question 1

Offloading Database Workload – AWS RDS Read Replication

Answer 1

Read replicas can be used to offload work from the main database

• • Writes go to the source instance;
• • Reads go to the read replica(s);

Question 2

how AWS RDS Read Replication works?

Answer 2

replication to read replicas is made asynchronously(not at the same time);
data is written to the source instance, and then replicated to the read replica(s)

Question 3

RDS Read Replication vs Multi-AZ failover deployments

Answer 3

– read replicas are built primarily for performance and offloading work.
– multi-AZ deployments are used for high availability and durability
– multi-AZ deployments give us synchronous replication instead of asynchronous.
– multi-AZ deployments are only used to perform a failover, they are idle the rest of the time.
– read replicas are used to serve legitimate traffic
it is often beneficial to use both of these as complements.

Question 4

pre-warming volume from a snapshot

Answer 4

by reading from every single block

Question 5

Potential Networking Issues

Answer 5

one of the primary network bottlenecks comes from EC2 instances

Question 6

Potential causes for bottlenecks

Answer 6

Instances are in different AZ, regions, or continents
BC2 instance sizes
not using enhanced networking features.

Question 7

check network performance

Answer 7

with iperf3

Question 8

VPCs

Answer 8

VPC peering to create a reliable connection

– No single point of failure for communication or bandwidth bottlenecks.

Question 9

Bandwidth limitations on your VPN to your AWS VPC

Answer 9

use AWS Direct connect

• • dedicated network connection
• • Sets up a private connection
• • Can reduce costs in some situations
• • supports port speeds of 1Gbps and 10 Gbps
• • Speeds of 50 Mbps, 100Mbps, 200Mbps, …and 500 Mbps can be ordered through an APN Partner supporting AWS Direct Connect.

Question 10

troubleshooting Auto Scaling Issues

Answer 10

• • use the wrong subnet
• • availability is no longer available or supported
• • security group does not exist
• • key pair associated does not exist
• • auto scaling configuration is not working correctly
• • instance type specification is not supported in that availability zone
• • auto scaling service is not enabled on the account.