I am trying to setup backup software (Bacula) on my home network and ran into a real dumb newbie DVD question I haven't been able to google an answer to (at least an answer I could understand) since I have never used writable DVDs before.
How does one write a iso filesystem onto a blank DVD+R disk without writing any files, and leaving the DVD writable (i.e, not finalized if that this the right term)? The growisofs and mkisofs man pages are mostly greek to me. Is there a magic cookbook incantation I can use until I can figure out all the techy details?
On 01/11/2010 02:40 PM, Stuart McGraw wrote:
I am trying to setup backup software (Bacula) on my home network and ran into a real dumb newbie DVD question I haven't been able to google an answer to (at least an answer I could understand) since I have never used writable DVDs before.
How does one write a iso filesystem onto a blank DVD+R disk without writing any files, and leaving the DVD writable (i.e, not finalized if that this the right term)? The growisofs and mkisofs man pages are mostly greek to me. Is there a magic cookbook incantation I can use until I can figure out all the techy details?\
It's pretty simple:
growisofs -Z /dev/dvd -R -J /path/file1 /path/file2 ...
When you want to add more files:
growisofs -M /dev/dvd -R -J /path/to/more/files ...
The magic is replacing the "-Z" (meaning "initialize session") with "-M" (merge data into session). When you finally want to close the session:
growisofs -M /dev/dvd=/dev/zero
which fills out the rest of the session with zeroes.
Hope that helps. ---------------------------------------------------------------------- - Rick Stevens, Systems Engineer ricks@nerd.com - - AIM/Skype: therps2 ICQ: 22643734 Yahoo: origrps2 - - - - 500: Internal Fortune Cookie Error - ----------------------------------------------------------------------
On 01/11/2010 02:56 PM, Rick Stevens wrote:
On 01/11/2010 02:40 PM, Stuart McGraw wrote:
I am trying to setup backup software (Bacula) on my home network and ran into a real dumb newbie DVD question I haven't been able to google an answer to (at least an answer I could understand) since I have never used writable DVDs before.
How does one write a iso filesystem onto a blank DVD+R disk without writing any files, and leaving the DVD writable (i.e, not finalized if that this the right term)? The growisofs and mkisofs man pages are mostly greek to me. Is there a magic cookbook incantation I can use until I can figure out all the techy details?\
It's pretty simple:
growisofs -Z /dev/dvd -R -J /path/file1 /path/file2 ...
When you want to add more files:
growisofs -M /dev/dvd -R -J /path/to/more/files ...
The magic is replacing the "-Z" (meaning "initialize session") with "-M" (merge data into session). When you finally want to close the session:
growisofs -M /dev/dvd=/dev/zero
which fills out the rest of the session with zeroes.
Is there also a way to read the different sessions (or states of the session)?
Stuart McGraw wrote:
I am trying to setup backup software (Bacula) on my home network and ran into a real dumb newbie DVD question I haven't been able to google an answer to (at least an answer I could understand) since I have never used writable DVDs before.
How does one write a iso filesystem onto a blank DVD+R disk without writing any files, and leaving the DVD writable (i.e, not finalized if that this the right term)? The growisofs and mkisofs man pages are mostly greek to me. Is there a magic cookbook incantation I can use until I can figure out all the techy details?
Growisofs with -Z option writes the first session, with -M writes the rest of the sessions. My feeling is that writing an empty filesystem on a media buys nothing and that's why there's no neat command to do it. If you don't want to write data then why write anything?
On 01/11/2010 04:09 PM, Bill Davidsen wrote:
Stuart McGraw wrote:
How does one write a iso filesystem onto a blank DVD+R disk without writing any files, and leaving the DVD writable (i.e, not finalized if that this the right term)?
Growisofs with -Z option writes the first session, with -M writes the rest of the sessions.
Ah, ok. I had tried the -Z option with a small file and thought I ended up with a finalized disk because bacula reported the disk had 0 bytes of free space left. But I may have misinterpreted what I was seeing (or its message may have been bogus.)
My feeling is that writing an empty filesystem on a media buys nothing and that's why there's no neat command to do it. If you don't want to write data then why write anything?
Because it's not me but the backup program that wants to write to the DVD and (I think) it wants a mounted DVD to write to. However, looking at another source of info, I may be wrong about that too.
Thanks for the info.
On 01/11/2010 03:36 PM, Stuart McGraw wrote:
On 01/11/2010 04:09 PM, Bill Davidsen wrote:
Stuart McGraw wrote:
How does one write a iso filesystem onto a blank DVD+R disk without writing any files, and leaving the DVD writable (i.e, not finalized if that this the right term)?
Growisofs with -Z option writes the first session, with -M writes the rest of the sessions.
Ah, ok. I had tried the -Z option with a small file and thought I ended up with a finalized disk because bacula reported the disk had 0 bytes of free space left. But I may have misinterpreted what I was seeing (or its message may have been bogus.)
Note that the command was "-Z /dev/dvd -R -J /file /file ..."
That's different than "-Z /dev/dvd=/path/to/isoimage" which WILL close the session. In other words, if there's an "=" in the command, the session will close as it will write the disk with the image AND fill it out with zeroes after to close the session.
My feeling is that writing an empty filesystem on a media buys nothing and that's why there's no neat command to do it. If you don't want to write data then why write anything?
Because it's not me but the backup program that wants to write to the DVD and (I think) it wants a mounted DVD to write to. However, looking at another source of info, I may be wrong about that too.
Thanks for the info.
You might want to take a look at the options for wodim as well, specifically the "-multi" and "-nofix" options. ---------------------------------------------------------------------- - Rick Stevens, Systems Engineer ricks@nerd.com - - AIM/Skype: therps2 ICQ: 22643734 Yahoo: origrps2 - - - - Perseverance: When you're too damned stubborn to say "I quit!" - ----------------------------------------------------------------------
Stuart McGraw wrote:
I am trying to setup backup software (Bacula) on my home network and ran into a real dumb newbie DVD question I haven't been able to google an answer to (at least an answer I could understand) since I have never used writable DVDs before.
How does one write a iso filesystem onto a blank DVD+R disk without writing any files, and leaving the DVD writable (i.e, not finalized if that this the right term)? The growisofs and mkisofs man pages are mostly greek to me. Is there a magic cookbook incantation I can use until I can figure out all the techy details?
FWIW, the concept you want to research is "multi-session". This is basically the same for both CD's and DVD's.
There is no need or advantage to "initialize" a blank DVD+R. As a matter of fact, there is no concept of doing that. The very first time a blank DVD is written in multi session all the necessary bits will be laid down. Also, remember that DVD+R is *write once*. Each time a new DVD session is written it will consume an additional amount of space to "replace" the previous TOC (Table of Contents) (Frankly, I don't recall if the new TOC contains the old TOC info or if the new TOC contains only new info and refers to the old TOC(s).) So, the more sessions you write to a DVD the more space that is consumed by the session information and the less space available for actual data.
In my history I first starting using DVD+R or DVD-R media to backup data. At that time DVD+RW or DVD-RW media were more expensive and I thought I was saving money. I switched to using DVD-RW media. But, as time when on I had more and more data that I felt needed to be backed up. But, since DVD's hold only 4GB there was plenty of manual intervention involved. This would cause me to avoid doing backups....
Now...or in my case years ago...hard drive prices came down quite a bit. Even though it was more expensive than it is today, convenience outweighed cost. I used an old PIII system as a headless file server with 2TB of backup space.
While I've heard that sw such as Bacula and Amanda are good solutions I don't use them. All of my important systems are Linux and I simply use rsync and crontab entries.