Link : https://leetcode.com/discuss/career/229177/My-System-Design-Template [@Topcat]
(1) FEATURE EXPECTATIONS [5 min]
(1) Use cases
(2) Scenarios that will not be covered
(3) Who will use
(4) How many will use
(5) Usage patterns
(2) ESTIMATIONS [5 min]
(1) Throughput (QPS for read and write queries)
(2) Latency expected from the system (for read and write queries)
(3) Read/Write ratio
(4) Traffic estimates
- Write (QPS, Volume of data)
- Read (QPS, Volume of data)
(5) Storage estimates
(6) Memory estimates
- If we are using a cache, what is the kind of data we want to store in cache
- How much RAM and how many machines do we need for us to achieve this ?
- Amount of data you want to store in disk/ssd
(3) DESIGN GOALS [5 min]
(1) Latency and Throughput requirements
(2) Consistency vs Availability [Weak/strong/eventual => consistency | Failover/replication => availability]
(4) HIGH LEVEL DESIGN [5-10 min]
(1) APIs for Read/Write scenarios for crucial components
(2) Database schema
(3) Basic algorithm
(4) High level design for Read/Write scenario
(5) DEEP DIVE [15-20 min]
(1) Scaling the algorithm
(2) Scaling individual components:
-> Availability, Consistency and Scale story for each component
-> Consistency and availability patterns
(3) Think about the following components, how they would fit in and how it would help
a) DNS
b) CDN [Push vs Pull]
c) Load Balancers [Active-Passive, Active-Active, Layer 4, Layer 7]
d) Reverse Proxy
e) Application layer scaling [Microservices, Service Discovery]
f) DB [RDBMS, NoSQL]
> RDBMS
>> Master-slave, Master-master, Federation, Sharding, Denormalization, SQL Tuning
> NoSQL
>> Key-Value, Wide-Column, Graph, Document
Fast-lookups:
-------------
>>> RAM [Bounded size] => Redis, Memcached
>>> AP [Unbounded size] => Cassandra, RIAK, Voldemort
>>> CP [Unbounded size] => HBase, MongoDB, Couchbase, DynamoDB
g) Caches
> Client caching, CDN caching, Webserver caching, Database caching, Application caching, Cache @Query level, Cache @Object level
> Eviction policies:
>> Cache aside
>> Write through
>> Write behind
>> Refresh ahead
h) Asynchronism
> Message queues
> Task queues
> Back pressure
i) Communication
> TCP
> UDP
> REST
> RPC
(6) JUSTIFY [5 min]
(1) Throughput of each layer
(2) Latency caused between each layer
(3) Overall latency justification
(7) OTHERS
Topics to read for System Design interviews:
- key features of distributed systems
- load balancing
- caching
- data partitioning
- indexes
- proxies
- redundancy & replication
- SQL vs NoSQL
- CAP theorem
- consistent hashing
- long polling
- web sockets
- server sent events
More => https://www.enjoyalgorithms.com/blog/design-youtube-system-design-interview-question