Re: [gentoo-user] How to build a time machine on Gentoo

[William Kenworthy <billk@iinet.net.au>]

On Wed, 2010-08-18 at 14:09 +0300, Nganon wrote:
> 
> 
> On 17 August 2010 22:34, Enrico Weigelt <weigelt@metux.de> wrote:
>         For things I'd like to keep an history (eg. /etc) I'm using
>         git, and
>         pushing the repo to a remote server (denying non-fastfoward
>         updates
>         there, so an theorectical highjacker cannot destroy my
>         history)
>         
> 
> Using git for /etc is a great idea. 
> Thanks. 
> 
Another option is:
*  app-backup/dirvish
      Latest version available: 1.2.1
      Latest version installed: 1.2.1
      Size of downloaded files: 47 kB
      Homepage:    http://www.dirvish.org/
      Description: Dirvish is a fast, disk based, rotating network
backup system.
      License:     OSL-2.0


Works by first creating a copy (--init) and then hard-linking subsequent
versions of files/directories back to the original original if its
identical.  If a file is changed/new, it is copied instead of linked so
actual space usage quickly stabilises even with a varying number of
versions.  Backup over the network (this is how I have configured mine)
uses rsync over ssh with keys and is "pull" from a cron job on the
backup server or manual on demand (i.e., server initiated).

Version management is by a reasonably sophisticated date of version
scheme where by running "dirvish-expire" deletes out of date versions
(runs in a cron job).  The smart part is that once the last hard link to
file is deleted, its gone, otherwise its kept in the remaining
versions :)

Restore is a simple matter of identifying the version you want and
copying it back - Ive restored individual files through to complete
systems after total disk failure.

Can do includes/excludes, whole systems or just directories such as /etc
and can be easily automated.

Doesnt use compression, but most backup regimes (every day for a weekly
rota + a Sunday kept for 6 months) stabilise at about 2x the original
(gross) copy size, no matter how many copies with average changes
between versions.  Though large scale changes such as an "emerge -e
world" will take more as it will generate new copies of most files.

Downside is it will hammer the destination file system - reiserfs3 works
well, ext2/ext3 have been hopeless everytime I've tried - mass
corruption.  The file system will need a large number of inodes (for
links) if there are an excessive number of files x versions - again
reiserfs3 scores well here.

Highly recommended!

BillK