Is redis cached in memory or hard disk?

Redis adopts an in-memory storage model with low latency, high throughput and scalability. Additionally, its key-value storage and memory eviction mechanism ensure efficient memory utilization, making it suitable for applications requiring fast data access.

Redis Cache in Memory

Redis is an in-memory database, which means it stores data In the computer's memory (RAM), not the hard drive. Memory is generally faster than a hard drive and can reduce latency in database operations.

Why does Redis choose memory?

Using memory instead of hard drive as the storage medium, Redis has the following advantages:

• Low latency: Memory is much faster than hard drive, This allows Redis to achieve faster read and write operations than traditional databases.
• High throughput: The memory can handle a large number of concurrent requests at the same time, improving the overall throughput of Redis.
• Scalability: Since Redis stores data in memory, its capacity can be easily expanded by adding more memory.

Memory Management of Redis

Redis uses a structure called a "key-value store" to store data. The key is a unique identifier and the value is the data associated with the key. Redis stores key-value pairs in a data structure called a hash table. Hash tables allow Redis to quickly find and access data without having to scan the entire data set.

In addition, Redis also uses a mechanism called "memory elimination" to manage memory usage. When memory is low, Redis deletes the least frequently used key-value pairs based on a specific policy such as least recently used (LRU). This ensures that Redis can efficiently utilize its available memory.

Conclusion

Redis chooses to store data in memory to achieve low latency, high throughput and scalability. Its memory management mechanism enables Redis to store and retrieve data efficiently, making it ideal for applications that require fast and reliable data access.

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