vitalif
/
zbackup
mirror of https://github.com/vitalif/zbackup
1
0
Fork 0
Code Issues Releases Wiki Activity

Change the introduction language a bit.

master
Konstantin Isakov 2013-07-18 22:58:59 +04:00
parent ac689b04ae
commit 4860cf98a5
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
README.md
View File

@ -1,6 +1,6 @@
# Introduction
**zbackup** is globally-deduplicating backup tool, based on the ideas found in [rsync](http://rsync.samba.org/). Feed a large `.tar` into it, and it will eliminate any duplicate blocks in it, then compress and optionally encrypt the result. Feed another `.tar` file, and it will not only eliminate any duplicate data in it, but also re-use any blocks found in any previous backups. This way only new changes are stored, and as long as the files are not very different, the amount of storage required is very low. The program is format-agnostic, so you can feed virtually any files to it (any types of archives, proprietary formats, even raw disk images -- but see [Caveats](#caveats)).
**zbackup** is globally-deduplicating backup tool, based on the ideas found in [rsync](http://rsync.samba.org/). Feed a large `.tar` into it, and it will store duplicate regions of it only once, then compress and optionally encrypt the result. Feed another `.tar` file, and it will also re-use any data found in any previous backups. This way only new changes are stored, and as long as the files are not very different, the amount of storage required is very low. Any of the backup files stored previously can be read back at any time. The program is format-agnostic, so you can feed virtually any files to it (any types of archives, proprietary formats, even raw disk images -- but see [Caveats](#caveats)).
This is achieved by sliding a window with a rolling hash over the input at a byte granularity and checking whether the block in focus was ever met already. If a rolling hash matches, an additional full cryptographic hash is calculated to ensure the block is indeed the same. The deduplication happens then.