Re: [Dvdrtools-users] Backup of a partition with compression

[Ekkehard Kraemer]

On Wed, 18 May 2005 05:36:32 +0200, Volker Kuhlmann <address@hidden> wrote:

> What actually happens? What commands did you use?

Sorry, can't reproduce the actual command now, but nothing fancy; roughly "gzip < /dev/hd.. | growisofs -Z /dev/dvd 
-stream-media-size=...". What happened was that the DVD is obviously burned (since it takes a while); there is no error 
message. "ls" on the DVD then shows a very big file (again, sorry, I don't have the exact size anymore). But when I 
try to actually read that large file, it stops quite soon (i.e. "gzip -d < /mnt/cdrom/file > /dev/null" or 
something like that reads a few KB from the file, and then aborts quickly with some "error reading from the file" 
message).

I don't think it's much to worry about, since it's quite excusable with the 2GB 
file size limit of ISO FS (that is the limit, isn't it?). One thing that could 
be improved would be if growisofs would refuse to create streamed files which 
are too big, or at least report a warning.

> The following should work:
>
> gzip </dev/... | growisofs -Z /dev/dvdrecorder=/dev/stdin

That sounds perfect, I'll try it and see how it works. I guess I can get back at the data 
with "dd if=/dev/dvd" or something like that?

> The problem with the above method is that you don't know when to stop
> reading,

No problem. The only case I'd want to get back at the data is to restore it on 
the same or another partition, and then the partition size has to be exactly 
the correct size anyway.

> so you should log the output of growisofs which gives you the
> number of blocks written.

Or that. :-)

Viele Grüße,
Ekkehard