blockyarchive
Blockyarchive/blkar (pronounced "bloc-kar") is a comprehensive utility for creating, rescuing, and general handling of SeqBox archives, with optional forward error correction
SeqBox is a single-file archive format designed by Marco Pontello that facilitates sector level data recovery for when file system metadata is corrupted/missing, while the archive itself still exists as a normal file on file system
Please visit the official SeqBox repo for the original implementation and technical details on this
Blockyarchive/blkar was formerly known as rust-SeqBox/rsbx prior to renaming
Comparison to the original SeqBox implementation/design
The original SeqBox implementation and format do not support repairing of data, only sector level recoverability
Blockyarchive allows repairs to be made by adding forward error correction (Reed-Solomon erasure code) to extended versions of SeqBox format (named Error-correcting SeqBox or EC-SeqBox for short), and also allows arranging the blocks in a burst error resistant pattern
Blockyarchive is also more robust compared to the original SeqBox implementation, as it does not assume the SBX container to be well formed, and makes as few assumptions about the SBX container as possible
blkar is overall based around osbx, but much more optimized
Features overall
- Data recovery that does not depend on file system metadata (sector level recovery)
- This allows data recovery even when data is fragmented and out of order
- Supports error correction (via Reed-Solomon erasure code) for EC-SeqBox
- Supports burst (sector) error resistance for EC-SeqBox
- JSON mode
- Outputs information in JSON format instead of human readable text, allowing easy integration with scripts
Limitations
- Only a single file is supported for encoding as SeqBox and EC-SeqBox are both single-file archive formats
- However, blkar may still be usable when you have multiple files, as blkar supports taking input from stdin during encoding, and also supports outputting to stdout during decoding
- This means if you have an archiver that supports bundling and unbundling on the fly with pipes, like tar, you can combine the use of the archiver and blkar into one encoding and decoding step
Goals
As blkar is to be used largely as a backup utility, security/robustness of the code will be prioritised over apparent performance
Status
This project has reached its intended feature completeness, so no active development for new features will occur. However, this project is still actively looked after, i.e. I will respond to PRs, issues, and emails, will consider feature requests, respond to bug reports quickly, and so on.
In other words, this is a completed project with respect to its original scope, but it is not abandoned
Getting started
Installation
blkar is available via AUR, GitHub releases or cargo
cargo install blkar
Usage guides & screencasts & other resources
The wiki contains comprehensive guides and resources
Note on Rust to Bash ratio
Just to avoid confusion, blkar is written purely in Rust, Bash is only used to write tests
Got a question?
Feel free to join the Gitter chat if you've got a question. You can email me directly as well.
Changelog
Specifications
SBX format (EC-SeqBox is also specified in this document)
Contributions
Contributions are welcome. Note that by submitting contributions, you agree to license your work under the same license used by this project (MIT).
Acknowledgement
I would like to thank Marco (the official SeqBox author) for discussing and clarifying aspects of his project, and also providing of test data during development of osbx. I would also like to thank him for his feedback on the numbering of the error correction enabled ECSBX versions (versions 17, 18, 19).
I would like to thank Ming for his feedback on the documentation, UX design, and several other general aspects of the osbx project, of which most of the designs are carried over to blkar, and also his further feedback on this project as well
The design of the readable rate in progress report text is copied from Arch Linux pacman's progress bar design
The design of block set interleaving arrangement in RS enabled versions is heavily inspired by Thanassis Tsiodras's design of RockFAT. The interleaving provides resistance against burst sector errors.
Donation
Note : Donation will NOT fuel development of new features. As mentioned above, this project is meant to be stable, well tested and well maintained, but normally I am not actively adding new features to it.
If blockyarchive has been useful to you, and you would like to donate to me for the development effort, you can donate through here
License
Libcrc code
The crcccitt code is translated from the C implementation in libcrc and are under the same MIT License as used by libcrc and as stated in libcrc source code, the license text of the crcccitt.c is copied over to crc-ccitt/build.rs, crc-ccitt/src/lib.rs, build.rs and src/crc_ccitt.rs as well
Official SeqBox code
The following files in tests folder copied from official SeqBox are under its license, which is MIT as of time of writing
- tests/SeqBox/*
All remaining files are distributed under the MIT license as stated in the LICENSE file