Ltarchiver is a backup program for long-term storage of files. Files are
stored as they are into the destination directory (no fancy formats that require decoding).
The difference between ltarchiver and a simple cp is that ltarchiver also keeps track of
where you stored what its checksum and also allows you to recover your file if gets corrupted.
Ltarchiver was built to satisfy my desire to have a tool that could not only store files on old unused media (mainly old hard-drives that I have lying around) without the fear that the files will suffer bitrot, and on the event that it does, to be able to restore the data.
To archive a file use the store command. For restore use the check_and_restore command.
ltarchiver-store [--non-interactive] <source file> <destination_directory>ltarchiver-restore <backup_file> <destination_directory>ltarchiver-refresh <destination_directory>Whenever you use the store command ltarchiver creates an entry in its book record to
know the checksum of the file, and where it was stored. When writing the file to
the destination ltarchiver also writes an ECC file that, if required by
the check_and_restore command, will be used to restore the file to its original
contents.
Currently the ECC file is about 1% of the size of original file. That allows for about 0.5% of the file (the ECC and the original files are added in this count) to be corrupted, assuming that the corruption is evenly spread across the backup media.
Of course not all corruptions can be expected to happen evenly, a disk scratch in a CD would likely corrupt several bytes that are close together while leaving many others completely unscathed. For this reason ltarchiver is not recommended for optical media. Not that it matters since optical media already employs some method of error recovery on damage.
Another problem that ltarchiver can't deal with is critical failures. For that reason ltarchiver should not be used with solid state media as those devices often fail completely. If critical failure is a concern for one reason or the other the user should opt for some kind of RAID setup.
btrfs comes with error recovery capabilities, but it's only useful for online-storage setups because btrfs keeps a checksum of each file and if it detects a corruption on the stored data it will revert the file to a previous correct version. That means that for the file-system to be able to use its self-healing capabilities, several versions of the same file must be stored. That wouldn't occour if the media you are using to store your backup is one that you keep stowed away and only plugs in when you need to store new files.
But even if you consider btrfs in an online storage scenario you would only be able to revert to a previous know version of a file. Not the current one.
- Clone this repository.
cdto the created directory.- Install the program with
pip.
git clone https://github.com/marceloslacerda/ltarchiver.git
cd ltarchiver
pip install .You might want to install this project inside a virtual environment or to force pip to do a user install.
Licensed under GPL 2. Check the license of c-ltarchiver for more information on schifra's dependency.