scripts for portable, incremental backups to external disk (or DVD)

[Les Mikesell]

M. Fioretti wrote:
> Greetings,
> 
> I have started to rethink from scratch my backup procedures
> and would like your suggestion on how to do what follows.
> 
> I want to write a script that makes total or incremental backups
> (depending on a command line switch) of selected directories
> of my computer on an external USB drive so that the drive
> content looks like, for example:
> 
> 20070809_complete            (complete backup of all selected
>                               files)
> 
> 20070810_incr                 (hard links to save space to the
>                                files in the last _complete folder
>                                plus copies of all files on the
>                                PC created or changed since previous
>                                _backup)
> 
> 20070812_incr                  same structure as 20070810_incr
> 
> etc...

Personally, I like backuppc running over the network from some other 
machine to do this grunge work automatically, but if you only have one 
machine I'd looke at rdiff-backup.

> (a complete backup would be 8+ GB of stuff)

These days you can get USB drives based on laptop hard drives that go up 
to 250 gigs and don't need external power.

> I know, or can figure out by myself, how to put together the basis of this
> with rsync. What I would like feedback on is about the best, that is
> fastest and most reliable, Fedora-compatible ways to:
> 
> create something that is completely readable with any operating system
> (including hidden files, links, long file names...): what if I need to
> recover files from there from a friend's Mac or Windows laptop? This is
> a filesystem question, so how would I format/ (re) create it?

With backuppc this happens automatically because you can access it 
through a web interface to browse and download files - but you need 
network access to the server.  With portable drives it will be hard to 
both maintain all attributes and be able to read it on anything. 
FAT-formatted USB drives are the only thing that will work across 
linux/windows/mac and like CD/DVD filesystems, it won't maintain all the 
attributes unless you write tar archives that will make it harder to 
access and keep rsync from working.
> 
> check periodically, as quickly as possible, that everything is still
> intact, that is that no single files or links etc... have been damaged.

Rsync will do this, if the disk format lets you use it.

> 
> Now a couple of OT question, answers to these are much better sent off list.
> 
> 1) What about reliability of hard disk versus DVD based backups?
>    Links to relevant reading are welcome.

Keep several copies, regardless.  Maybe your best solution is to use an 
ext3 USB drive as the main backup, preserving attributes and do separate 
DVDs or VFAT disks for the files you might want to use elsewhere.  Or if 
you have internet access to a remote machine, rsync over ssh works 
nicely, with or without backuppc driving it.


> 2) Any positive or negative feedback about Lacie external USB 2.0 drives?
>    (the store at the corner has an offer on the 300968E model...)

The worst thing about portable drives is the power connector for the 
ones that need external power.  If you plan to move it around, I'd 
recommend one of the new laptop-drive based versions that run off USB 
power, or a flash based version if you only need 8 gigs.

-- 
   Les Mikesell
    lesmikesell at gmail.com