Re: Getting started with Tarsnap

[Daniel Staal <DStaal@usa.net>]

--As of February 12, 2014 6:54:01 PM +0000, jg5 is alleged to have said:

> 1). On the Tarsnap general usage page, can anyone please tell me what the
> following means:
>
> "The examples here assume that you are using a Tarsnap configuration file
> including keyfile and cachedir directives."
>
> What are 'keyfile and cachedir directives'?  Are they simply instructions
> to the operating system to put the keyfile and cache directory in
> specific locations?

Close - they are instructions to *tarsnap* on where the files are.  They 
look something like this (from my tarsnap.conf file, on FreeBSD):

~~~
# Tarsnap cache directory
cachedir /usr/local/tarsnap-cache

# Tarsnap key file
keyfile /root/tarsnap.key
~~~

If you haven't run tarsnap yet, they may not exist.  This is generally ok. 
(At this point.)

> 2). I don't appear to have the /usr/local/tarsnap-cache directory.  Can
> anyone suggest what might have happened and what I should do about it?
> Does this mean that Tarsnap hasn't installed properly? Should I
> re-install? Or should I just run 'tarsnap --fsck'?

It probably means the installer didn't create it, for whatever reason. 
(After all, you might want it someplace else, or a package manager could 
have created it someplace else for you.)  You could create it manually, or 
run `tarsnap --fsck`.

> 3). Can anyone point me to a step-by-step guide - online article,
> whatever - on how to use Tarsnap? I think it's a great idea, and I need
> to sort out a backup system, but am wondering if it's maybe a bit over my
> head. Thought I would ask on this forum to see if things become clearer
> before calling it a day.

If you have gotten this far, and have a keyfile, you are almost done.  It's 
simpler than it sounds.  (If you *don't* have a keyfile, run 
`tarsnap-keygen --keyfile $KEY_LOCATION --user $USERNAME --machine 
$MACHINENAME`, where $KEY_LOCATION is the location you want the keyfile to 
be (whatever you've got in your tarsnap.conf, $USERNAME is whatever you 
signed on to the tarsnap site with, and $MACHINENAME is whatever you want 
to call this machine.)

Then make sure you have the tarsnap-cache directory (see above), and you 
are set up.  The only thing left is to actually create the backups.  That's 
done using something like this:

tarsnap -cf $BACKUPNAME /your/backed/up/directory

Where $BACKUPNAME is whatever you want to call that backup - I usually use 
something like 'settings-`date +\%F`', which will automatically add the 
current date to the name.  (Check your man pages - `date` is standard, but 
it's options aren't...)  The man pages describe other options.  (I like 
`--humanize-numbers` personally.)

To get that backup back, you need the command:

tarsnap -xf $BACKUPNAME

Where $BACKUPNAME is the name of the backup you want to retrieve - as 
specified in the create command.  (`-c` is create, `-x` is extract.  `-f` 
is the name of the 'backup file', even though there is no actual 'file'; 
it's using the same syntax as tar.)  Again, check the man pages for other 
options and details on exactly what that will do.

Hope that helps, and was a bit clearer.  ;)

Daniel T. Staal

---------------------------------------------------------------
This email copyright the author.  Unless otherwise noted, you
are expressly allowed to retransmit, quote, or otherwise use
the contents for non-commercial purposes.  This copyright will
expire 5 years after the author's death, or in 30 years,
whichever is longer, unless such a period is in excess of
local copyright law.
---------------------------------------------------------------