# Managing Cache

Effectively managing the data cached in Alluxio is key to achieving maximum performance and resource efficiency. This section provides a comprehensive overview of the data caching lifecycle in Alluxio, from loading data into the cache to managing its presence and eventual removal.

## The Data Cache Lifecycle

We can think of the life of cached data in three main phases:

1. **Loading Data**: How data gets into the cache in the first place.
2. **Managing Data**: How to control what is cached, how much space it uses, and for how long.
3. **Removing Data**: How data is evicted or deleted from the cache.

### Loading Data into the Cache

This guide covers the two primary ways data is loaded into Alluxio.

* **Passive Caching**: The default behavior where data is automatically cached the first time it is read by an application.
* **Active Preloading**: Proactively loading data into the cache *before* it is needed using the distributed `job load` command. This is ideal for warming up the cache for performance-sensitive workloads.

Learn more about [Loading Data](https://documentation.alluxio.io/ee-ai-en/ai-3.7/cache/loading-data-into-the-cache)...

### Managing Data in the Cache

Once data is in the cache, Alluxio provides a powerful set of tools to control its lifecycle and resource consumption.

* **Cache Filter Policies**: Define rules to selectively cache or ignore files based on their path. This is crucial for managing mutable data and optimizing cache space.
* **Cache Quotas**: Set limits on the amount of cache space a specific directory tree can consume, which is essential for multi-tenancy and resource isolation.
* **Time-to-Live (TTL)**: Automatically expire and evict cached data after a defined period, ensuring that stale or temporary data is cleaned up.
* **Eviction Priority**: Assign priorities to different datasets to influence which data is evicted first when the cache is full, protecting critical data from being removed.

Learn more about [Managing Data](https://documentation.alluxio.io/ee-ai-en/ai-3.7/cache/managing-data-in-the-cache)...

### Removing Data from the Cache

This guide details the different ways data is removed from the Alluxio cache, either automatically or manually.

* **Automatic Eviction**: The standard process where Alluxio removes data based on policies like LRU (Least Recently Used) when the cache reaches its capacity.
* **Manual Eviction**: Forcibly remove specific files or directories from the cache using the `job free` command, giving you direct control over cache contents.
* **Stale Cache Cleaning**: A specialized administrative tool to find and remove misplaced or redundant data that can occur after cluster topology changes.

Learn more about [Removing Data](https://documentation.alluxio.io/ee-ai-en/ai-3.7/cache/removing-data-from-the-cache)...