# bcache

> disk caching software in the Linux kernel

**Wikidata**: [Q16991599](https://www.wikidata.org/wiki/Q16991599)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Bcache)  
**Source**: https://4ort.xyz/entity/bcache

## Summary
Bcache is a Linux kernel module that functions as disk caching software, allowing it to create a logical hybrid drive by combining fast storage devices with slower ones to improve performance. It operates as a logical volume caching software within the Linux kernel environment and was succeeded by the more advanced Bcachefs filesystem.

## Key Facts
- bcache is a Linux kernel module that functions as disk caching software
- It is licensed under the GNU General Public License
- bcache is part of the Linux kernel
- It was followed by Bcachefs, a more advanced Linux filesystem
- bcache is an instance of free software and logical volume caching software
- The project's website is http://bcache.evilpiepirate.org/
- Its source code is available at http://evilpiepirate.org/git/linux-bcache.git
- It has a presence on Stack Exchange at https://stackoverflow.com/tags/bcache
- It is documented in Arch Wiki and Gentoo Wiki
- The project is written in the C programming language

## FAQs
### Q: What is bcache used for?
A: bcache is used as disk caching software in the Linux kernel to create a logical hybrid drive by combining fast storage devices with slower ones to improve overall system performance.

### Q: How does bcache work?
A: bcache operates as a caching layer for block devices in the Linux kernel, allowing users to use SSDs as cache for slower storage devices like HDDs, which improves read/write speeds without requiring data to be stored twice.

### Q: What's the difference between bcache and Bcachefs?
A: bcache is a block device caching layer, while Bcachefs is a complete filesystem with volume management, caching capabilities, checksumming, and snapshot features that succeeded bcache as a more comprehensive solution.

### Q: How do I implement bcache on my Linux system?
A: bcache can be implemented by configuring it through sysfs interface, setting up backing devices, cache devices, and then attaching them to create the cached block device, which can then be formatted and mounted like any other block device.

## Why It Matters
bcache addresses the common performance bottleneck in Linux systems by providing an efficient caching layer for storage devices. In an era where SSD prices were prohibitively expensive for large storage needs, bcache allowed users to combine the speed of smaller SSDs with the capacity of larger HDDs, creating cost-effective hybrid storage solutions. This technology was particularly significant for servers and high-performance computing systems where storage I/O performance was critical. By implementing an intelligent caching mechanism at the block layer, bcache improved overall system responsiveness without requiring significant hardware upgrades. Its development paved the way for more sophisticated storage technologies like Bcachefs, which incorporated many of bcache's concepts while adding additional filesystem features. The open-source nature of bcache, licensed under the GPL, allowed it to be widely adopted and modified across different Linux distributions, contributing to the evolution of Linux storage solutions.

## Notable For
- bcache is one of the first widely adopted software caching solutions implemented directly in the Linux kernel
- It pioneered the use of SSD caching for HDD storage at the block device level in Linux systems
- bcache was developed before the commercialization of hybrid drives, providing a software alternative to hardware-based caching solutions
- It served as the foundation for the more advanced Bcachefs filesystem
- bcache provides automatic cache management without requiring manual intervention or specialized hardware

## Body
### Overview
Bcache is a Linux kernel module that functions as disk caching software. It allows for the creation of logical hybrid drives by combining fast storage devices with slower ones to improve overall performance. The project is licensed under the GNU General Public License and is considered free software.

### Technical Details
- bcache operates as a logical volume caching software package or component
- It creates a logical hybrid drive by implementing a caching layer for block devices
- The project is written in the C programming language
- Its source code is hosted at http://evilpiepirate.org/git/linux-bcache.git
- It has been documented in both Arch Wiki and Gentoo Wiki resources
- bcache has a presence on Stack Exchange for community support and troubleshooting

### Development and Ecosystem
- bcache is part of the Linux kernel
- It has a project website at http://bcache.evilpiepirate.org/
- The project has been followed by the development of Bcachefs, a more advanced filesystem
- bcache has 2 sitelinks, indicating limited documentation presence compared to larger projects
- It supports multiple languages including English and Norwegian

### Related Projects
- Bcachefs is a related Linux filesystem supporting volume management, caching, checksumming, and snapshots
- Bcachefs represents an evolution beyond bcache, incorporating more comprehensive filesystem features
- The two projects share conceptual similarities but serve different roles in the Linux storage ecosystem

## References

1. Quora