A practitioner's guide to building scalable systems

Building Scalable Systems: Distributed Systems basics to System Design Interviews

We want to give you the tools to compare multiple approaches and pick the one that works for your scenario.

Grokking the Distributed and Scalable Systems

# Why are operations inside a Node reliable?

The operations inside a node are reliable because of the following reasons:

1. Operations follow a certain order
2. Nodes fail as a unit

## Operations follow a certain order
You can tell with certainty that what was the order of two operations. For simplicity, you can imagine that every operation in Node executes on a single thread.  This makes it easy to reason about the state transitions

>*It can become a little tricky if the process is using multiple threads but it is still possible to reason about the sequence of operations within a single request that's being processed by the Node.*

## Nodes fail as a unit
A Node can fail due to following reasons:

### 1. Hardware failures

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Hardware failures are a common occurrence in distributed systems. Common examples are 
* Disk failures
* RAM corruption
* Processor malfunctions due to overheating etc.

### 2. Software crashes
### 3. Power outages
### 4. Natural Disasters
![](/api/collection/5689413791121408/5645316556587008/page/5746664899870720/image/5660765553950720)
### 5. Logical errors e.g. out of memory or disk space

When a Node fails, it is removed from the Network and the distributed system is expected to continue serving customers. This is known as fault tolerance - a topic which we will discuss in detail later.

What and Why

Node in a Distributed System

Performance and Numbers

Fault Tolerance and Availability

Understanding TIME in Distributed Systems

Data Centers for software engineers

Scaling Distributed Systems

Load Balancers

Structured Storage at Scale

Sharding in Storage Systems

SQL vs NO-SQL

Blob Storage at Scale

Caching in Distributed Systems

Queues and Asynchronous Processing

Data Analytics and Batch Processing

Logging and Monitoring

Searching at Scale

Conclusion

Nodes are reliable but Edges are not

Why are operations inside a Node reliable?

Operations follow a certain order