Foreword
Attic is a secure backup program for Linux, FreeBSD and Mac OS X.
Attic is designed for efficient data storage where only new or
modified data is stored.
Features
- Space efficient storage
- Variable block size deduplication is used to reduce the number of bytes
stored by detecting redundant data. Each file is split into a number of
variable length chunks and only chunks that have never been seen before
are compressed and added to the repository.
- Optional data encryption
- All data can be protected using 256-bit AES encryption and data integrity
and authenticity is verified using HMAC-SHA256.
- Off-site backups
- Attic can store data on any remote host accessible over SSH as
long as Attic is installed.
- Backups mountable as filesystems
- Backup archives are mountable as
userspace filesystems for easy backup verification and restores.
Glossary
- Deduplication
- Deduplication is a technique for improving storage utilization by
eliminating redundant data.
- Archive
- An archive is a collection of files along with metadata that include file
permissions, directory structure and various file attributes.
Since each archive in a repository must have a unique name a good naming
convention is hostname-YYYY-MM-DD.
- Repository
- A repository is a filesystem directory storing data from zero or more
archives. The data in a repository is both deduplicated and
optionally encrypted making it both efficient and safe. Repositories are
created using attic init and the contents can be listed using
attic list.
- Key file
- When a repository is initialized a key file containing a password
protected encryption key is created. It is vital to keep this file safe
since the repository data is totally inaccessible without it.