Database

Question 1

DynamoDB 101:

Answer 1

NoSQL, fast and flexible, consistent, single-digit millisecond latency at any scale. Stored on SSD; Spread Across 3 Geo distinct datacentres;

Question 2

DynamoDB Consistency Mode:

Answer 2

Eventual Consistency Reads (Best read performance) and Strong Consistency Reads

Question 3

DynamoDB Pricing:

Answer 3

Storage,Provisioned Capacity Unit(Read and Write, Write is much more expensive)

Question 4

Redshift 101:

Answer 4

fast,powerful,fully managed, petabyte-scale OLAP service; scalable from $0.25 per hour to $1000 per terabyte*year. less than 1/10 of the cost for other datawarehousing solutions.

Question 5

Redshift Configuration:

Answer 5

Single Node 160Gb; Multi-Node:LeaderNode(manages client connections and receives queries),Compute Node(up to 128 in qty to store data and perform queries and computations.)

Question 6

Redshift Performance and Features:

Answer 6

(10 times faster)Columnar Data Storage;Advanced Compression (Columnar based data easily compressed much more by automatic sampleing data and select most suitable compression scheme);Massive Parallel Processing(MPP,automatic distribution across all nodes)

Question 7

Redshift Pricing:

Answer 7

Compute Node Hours(leader node free);backup;Data Transfer(only within a VPC, not outside it);

Question 8

Redshift Security:

Answer 8

Encrypt in transit using SSL;Encryted at rest using AES-256;Default cover key management with other options such as HSM and AWS KMS

Question 9

Redshift Availability:

Answer 9

currently only available in 1 AZ as it does not needs redundancy and you outage recovery could be achieved from snapshot.

Question 10

Elasticache 101:

Answer 10

a web-based in-memory cloud cache service that is easy to deploy,operate and scale;It helps to take loads off of your disk-based databses.

Question 11

Elasticache Scenario:

Answer 11

significantly improve latency and throughput for read-heavy application workloads(social media networking, gaming, media sharing and Q&A portals);compute-intensive workloads(recommendation engine etc.)

Question 12

Elasticache Types:

Answer 12

Memcached and Redis(open-source,sorted set and lists,Master/Slave appplication and Multi-AZ)

Question 13

Elasticache Exam Tips:

Answer 13

good for read heavy not prone to frequent changing;allevite database from heavy loads OLAP transactions

Question 14

Aurora 101:

Answer 14

MySQL-compatible high-end commercial database solution provides up to five performance or similar performance and availablity at 1/10 price.

Question 15

Aurora Scaling:

Answer 15

Start with 10GB and autoscaling with a step of 10GB increments to 64TB;Compute resources up to 32vCPUs and 244GB Memory;

Question 16

Aurora Availability:

Answer 16

2 copy per AZ*3 AZ = 6 copies; tolerant of 2 copies loss for write availablity and 3 copies loss for read availablity

Question 17

Aurora Replicas:

Answer 17

up to 15 Aurora Replicas and 5 MySQL Read Replicas(NOT support automatic failover)