How do the features and operation of in-memory databases differ from traditional data storage systems?

In-memory databases store all data in RAM, which provides very high speed of access and processing compared to traditional databases that store data on disks.

Main differences:

• Speed: in-memory databases operate faster due to the absence of disk read/write operations.
• Resilience: traditional databases usually save data on disk, ensuring data safety in case of failures, whereas in-memory databases require additional mechanisms for data preservation (e.g., periodic dumps to disk).
• Data volume: the amount of data in in-memory databases is limited by the available RAM size.
• Usage: in-memory databases are often used for caching, real-time analytics, and high-performance applications.

Example: Redis — a popular in-memory database that stores data in memory for quick access.