[olug] Split 7zip archives and restoring...

Kristian Erik Hermansen kristian.hermansen at gmail.com
Sun Feb 3 08:26:07 UTC 2008

On Feb 3, 2008 12:11 AM, Dan Linder <dan at linder.org> wrote:
> I'm trying to backup my home directory to DVD.  I though I'd use 7-Zip
> (available in most distributions).  It doesn't allow to write directly to
> DVD so I have it create 50MB slices, and then once I get 4.4GB of slices, I
> back them up.  The command I used is this:
>   7z a -v50m /home/dan.backup/full-20080202.7z /home/dan/ -x!dan/Backups/*
> This seemed to work for the backup -- my /home/dan.backup/ directory has
> numerous "full-20080202.7z.###" (where ### starts at 001).
> Before I reinstalled my system I wanted to test the backup files.  I thought
> it would be something as simple as
> 1: "7z t full-20080202.7z.001" it reports "Testing full-20080202.7z.001" and
> then "Everyting is Ok".
>  - I know this is not true because I ran this against only the first three
> pieces of a 200+ slice archive.
> 2: "7z l full-20080202.7z.001" (to see what files it has inside), It lists
> the following:
>    Date      Time    Attr         Size   Compressed  Name
> ------------------- ----- ------------ ------------
> ------------------------
> 2008-02-03 00:15:53        11933164371  11933164371  full-20080202.7z
> ------------------- ----- ------------ ------------
> ------------------------
>                            11933164371  11933164371  1 files, 0 folders
> 3: Thinking that maybe I needed to use the original "full-20080202.7z" name,
> I tried "7z t full-20080202.7z".  It reports "there is no such archive"
>  - This makes sense since that file doesn't exist. :-)
> 4: I finally just tried this: "7z x -r full-20080202.7z.001" and I got a
> large (but partial) file "full-20080202.7z".  (But it appears this file is
> broken and 7z won't even test nor extract...)
> The 7Zip documentation and website are quite lite on their notes on this.
> Anyone else worked with 7z and splitting large archive files?
> I started using "rar" but it was quite a bit slower than 7z and from what I
> read it didn't handle things well if one of the archive slices was missing
> or broken.

Do you know about mondorescue?  Better solution that trying to
reimplement it yourself :-)
Kristian Erik Hermansen
"Know something about everything and everything about something."

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