Bcachefs is a copy-on-write file system for Linux-based operating systems.
Few weeks ago we share here on the blog the news about the acceptance of the Bcachefs file system in the linux-next branch, since in the main branch was rejected by Linus Torvalds and recommended Kent Overstreet first evaluate the suitability of the proposed patches in the Linux-next experimental branch, so if the review is successful, BcacheFS could be included in the 6.7 kernel.
After almost a month of work (since the last attempt to integrate BcacheFS into the main branch), Linus Torvalds has finally given the go-ahead and approved the request to include BcacheFS in the main branch of the Linux Kernel and added the Bcachefs implementation to the repository in which the 6.7 kernel branch is being developed, expected to be released in early January.
As already mentioned in the article we shared previously, Attempts to promote BcacheFS to the Linux main branch began in 2020, after which it took almost three more years to eliminate the comments and deficiencies identified after peer review.
An updated set of patches was proposed during this year, which were rejected several times, but was finally accepted into the Linux-next branch in September, with the intention of testing features for future versions of the Linux kernel.
For those who do not know about BcacheFS, you should know that there is a file system what is developing using technologies already proven in the development of the Bcache block device, designed to cache slow hard drive access onto fast SSDs with an emphasis on reliability and robustness and the full set of features one would expect from a modern file system.
- Copy on write (COW), such as zfs or btrfs
- Full data and metadata checksum
- Multiple devices
- Replication
- Erasure coding (not stable)
- Caching, data location
- Compression
- Encryption
- Snapshots
- Now mode
- Reflink
- Extended attributes, ACLs, quotas
- Scalable – Tested at over 100TB and expected to scale much higher (testers wanted!)
- High performance, low tail latency
In addition to this, BcacheFS attempts to combine the performance, reliability and scalability of XFS with advanced functionality found in Btrfs and ZFS, such as multi-device partitioning, multi-layer drive layouts, replication (RAID 1/10), caching, transparent data compression (LZ4), gzip and ZSTD modes), state sectors , integrity verification using checksums, the ability to store Reed-Solomon error correction codes (RAID 5/6), storage of information in encrypted form (ChaCha20 and Poly1305 are used).
In terms of performance, Bcachefs is ahead of Btrfs and other filesystems based on the copy-on-write mechanism and demonstrates an operating speed close to Ext4 and XFS.
The patch added to the kernel includes around 95 thousand lines of code. The project has been developed for over 10 years by Kent Overstreet, who also developed the Bcache block device caching system on SSD drives included in the kernel.
A special feature of Bcachefs is the support for multi-unit connections layers, in which the storage is made up of several layers: the fastest drives (SSD) are connected to the bottom layer, which is used to cache frequently used data, and the top layer is made up of disk drives more spacious and economical that provide storage for less used data.
Caching can be used between layers in write-back mode. Drives can be dynamically added and detached from a partition without stopping use of the file system (data migrates automatically).
finally if you are interested in being able to try this file system on your own, you should know that you must compile a Kernel for a user. You can follow the instructions at following link
For those who can learn more about it, you can consult the details in the following link