Resilient architecture

Question 1

4 design pillars

Answer 1

1. resilient storage
2. decoupling mechanisms
3. Multi-tier architecture solution
4. Design highly available/fault tolerant systems

Question 2

EC2 Instance store is …

Answer 2

ephemeral volume

Question 3

EC2 instance store should use for …

Answer 3

caching/temporary data which is replicated somewhere else

Question 4

Elastic Block Store connects to …

Answer 4

one EC2 instance at a time.

Question 5

EBS supports two things

Answer 5

1. Encryption

2. Snapshots

Question 6

EBS and EC2 lifecycle is …

Answer 6

independent

Question 7

EBS has 4 types

Answer 7

1. gp2 - general SSD
2. IOPS SSD
3. st1 - throughput optimezed HDD
4. sc1 - cold HDD

Question 8

SSD is good for

Answer 8

random access

Question 9

HDD is good for

Answer 9

sequential access

Question 10

Amazon EFS is

Answer 10

File storage in the cloud

Question 11

Amazon EFS can be connected to …

Answer 11

multiple EC2 instance.

Question 12

Amazon EFS is compatible with

Answer 12

linux based AMIs for EC2 but not for Windows.

Question 13

Amazon EFS connects through

Answer 13

mount points

Question 14

Amazon EFS can connect to …

Answer 14

a single VPC at a time.

Question 15

Amazon S3 consistency model

Answer 15

Strong consistency for no object response.

Eventual cons. for updates.

Question 16

RTO

Answer 16

Recovery Time Objective - how long does it take to recover

Question 17

RPO

Answer 17

Recovery Point Objective - how much data is lost, could be measured in bytes or in time.

Question 18

4 test axioms for resilience

Answer 18

1. “Single AZ” is never the good answer.
2. Managed service is always preferred.
3. High availability < Fault tolerant = errors are concealed and there is no loss of service
4. Expect everything will fail at some point and plan accordingly.