What are disk cache eviction policies and how do they work?

What are disk cache eviction policies and how do they work?

Disk cache eviction policies determine how data is removed from the cache when it becomes full. Common policies include LRU (Least Recently Used), FIFO (First In, First Out), and LFU (Least Frequently Used). Each has its own strategy for deciding which data to evict.

Can you explain LRU in more detail?

Sure! LRU stands for Least Recently Used. It keeps track of the order in which items are accessed and evicts the least recently accessed item when space is needed. This is based on the assumption that data accessed recently will likely be accessed again soon.

What are the advantages of using FIFO?

FIFO, or First In, First Out, is simple to implement and ensures that older data is removed first. It's useful in scenarios where the age of data is more important than how often it is accessed.

Are there any drawbacks to these policies?

Yes, each policy has its drawbacks. LRU can be complex and resource-intensive to implement, while FIFO may evict frequently used data simply because it was added earlier. LFU can also be inefficient if access patterns change.