--- /dev/null
+%%
+%%
+
+\section*{DVD Volumes}
+\label{_DVDChapterStart}
+\index[general]{DVD Volumes}
+\index[general]{Writing DVDs}
+\index[general]{DVD Writing}
+\index[general]{Volumes!DVD}
+\addcontentsline{toc}{section}{DVD Volumes}
+
+Bacula allows you to specify that you want to write to DVD. However,
+this feature is implemented only in version 1.37 or later.
+You may in fact write to DVD+RW, DVD+R, DVD-R, or DVD-RW
+media. The actual process used by Bacula is to first write
+the image to a spool directory, then when the Volume reaches
+a certain size or, at your option, at the end of a Job, Bacula
+will transfer the image from the spool directory to the
+DVD. The actual work of transferring the image is done
+by a script {\bf dvd-handler}, and the heart of that
+script is a program called {\bf growisofs} which allows
+creating or adding to a DVD ISO filesystem.
+
+You must have {\bf dvd+rw-tools} loaded on your system for DVD writing to
+work. Please note that the original {\bf dvd+rw-tools} package does {\bf
+NOT} work with Bacula. You must apply a patch which can be found in the
+{\bf patches} directory of Bacula sources with the name
+{\bf dvd+rw-tools-5.21.4.10.8.bacula.patch}.
+
+The fact that Bacula cannot use the OS to write directly
+to the DVD makes the whole process a bit more error prone than
+writing to a disk or a tape, but nevertheless, it does work if you
+use some care to set it up properly. However, at the current time
+(28 October 2005) we still consider this code to be experimental and of
+BETA quality. As a consequence, please do careful testing before relying
+on DVD backups in production.
+
+The remainder of this chapter explains the various directives that you can
+use to control the DVD writing.
+
+\label{DVDdirectives}
+
+\subsection*{DVD Specific SD Directives}
+\index[general]{Directives!DVD}
+\index[general]{DVD Specific SD Directives }
+\addcontentsline{toc}{subsection}{DVD Specific SD Directives}
+
+The following directives are added to the Storage daemon's
+Device resource.
+
+\begin{description}
+
+\item [Requires Mount = {\it Yes|No}]
+ \index[sd]{Requires Mount }
+ You must set this directive to {\bf yes} for DVD-writers, and to {\bf no} for
+ all other devices (tapes/files). This directive indicates if the device
+ requires to be mounted using the {\bf Mount Command}.
+ To be able to write a DVD, the following directives must also be
+ defined: {\bf Mount Point}, {\bf Mount Command}, {\bf Unmount Command} and
+ {\bf Write Part Command}.
+
+\item [Mount Point = {\it directory}]
+ \index[sd]{Mount Point}
+ Directory where the device can be mounted.
+
+\item [Mount Command = {\it name-string}]
+ \index[sd]{Mount Command}
+ Command that must be executed to mount the device. Although the
+ device is written directly, the mount command is necessary in
+ order to determine the free space left on the DVD. Before the command is
+ executed, \%a is replaced with the Archive Device, and \%m with the Mount
+ Point.
+
+ Most frequently, you will define it as follows:
+
+\footnotesize
+\begin{verbatim}
+ Mount Command = "/bin/mount -t iso9660 -o ro %a %m"
+\end{verbatim}
+\normalsize
+
+\item [Unmount Command = {\it name-string}]
+ \index[sd]{Unmount Command}
+ Command that must be executed to unmount the device. Before the command is
+ executed, \%a is replaced with the Archive Device, and \%m with the Mount
+ Point.
+
+ Most frequently, you will define it as follows:
+
+\footnotesize
+\begin{verbatim}
+ Unmount Command = "/bin/umount %m"
+\end{verbatim}
+\normalsize
+
+\item [Write Part Command = {\it name-string}]
+ \index[sd]{Write Part Command }
+ Command that must be executed to write a part to the device. Before the
+ command is executed, \%a is replaced with the Archive Device, \%m with the
+ Mount Point, \%e is replaced with 1 if we are writing the first part,
+ and with 0 otherwise, and \%v with the current part filename.
+
+ For a DVD, you will most frequently specify the Bacula supplied {\bf
+ dvd-handler} script as follows:
+
+\footnotesize
+\begin{verbatim}
+ Write Part Command = "/path/dvd-handler %a write %e %v"
+\end{verbatim}
+\normalsize
+
+ Where {\bf /path} is the path to your scripts install directory, and
+ dvd-handler is the Bacula supplied script file.
+ This command will already be present, but commented out,
+ in the default bacula-sd.conf file. To use it, simply remove
+ the comment (\#) symbol.
+
+
+\item [Free Space Command = {\it name-string}]
+ \index[sd]{Free Space Command }
+ Command that must be executed to check how much free space is left on the
+ device. Before the command is executed,\%a is replaced with the Archive
+ Device, \%m with the Mount Point, \%e is replaced with 1 if we are writing
+ the first part, and with 0 otherwise, and \%v with the current part filename.
+
+ For a DVD, you will most frequently specify the Bacula supplied {\bf
+ dvd-handler} script as follows:
+
+\footnotesize
+\begin{verbatim}
+ Free Space Command = "/path/dvd-handler %a free"
+\end{verbatim}
+\normalsize
+
+ Where {\bf /path} is the path to your scripts install directory, and
+ dvd-freespace is the Bacula supplied script file.
+ If you want to specify your own command, please look at the code in
+ dvd-handler to see what output Bacula expects from this command.
+ This command will already be present, but commented out,
+ in the default bacula-sd.conf file. To use it, simply remove
+ the comment (\#) symbol.
+
+ If you do not set it, Bacula will expect there is always free space on the
+ device.
+
+\end{description}
+
+In addition to the directives specified above, you must also
+specify the other standard Device resource directives. Please see the
+sample DVD Device resource in the default bacula-sd.conf file. Be sure
+to specify the raw device name for {\bf Archive Device}. It should
+be a name such as {\bf /dev/cdrom} or {\bf /media/cdrecorder} or
+{\bf /dev/dvd} depending on your system. It will not be a name such
+as {\bf /mnt/cdrom}.
+
+
+\subsection*{DVD Specific Director Directives}
+\index[general]{Directives!DVD}
+\index[general]{DVD Specific Director Directives }
+\addcontentsline{toc}{subsection}{DVD Specific Director Directives}
+
+The following directives are added to the Director's Job resource.
+
+\label{WritePartAfterJob}
+\begin{description}
+\item [Write Part After Job = \lt{}yes|no\gt{}]
+ \index[dir]{Write Part After Job }
+ If this directive is set to {\bf yes} (default {\bf no}), the
+ Volume written to a temporary spool file for the current Job will
+ be written to the DVD as a new part file
+ will be created after the job is finished.
+
+ It should be set to {\bf yes} when writing to devices that require a mount
+ (for example DVD), so you are sure that the current part, containing
+ this job's data, is written to the device, and that no data is left in
+ the temporary file on the hard disk. However, on some media, like DVD+R
+ and DVD-R, a lot of space (about 10Mb) is lost everytime a part is
+ written. So, if you run several jobs each after another, you could set
+ this directive to {\bf no} for all jobs, except the last one, to avoid
+ wasting too much space, but to ensure that the data is written to the
+ medium when all jobs are finished.
+
+ This directive is ignored for devices other than DVDs.
+\end{description}
+
+
+
+\label{DVDpoints}
+\subsection*{Other Points}
+\index[general]{Points!Other }
+\index[general]{Other Points }
+\addcontentsline{toc}{subsection}{Other Points}
+
+\begin{itemize}
+\item Writing and reading of DVD+RW seems to work quite reliably
+ provided you are using the patched dvd+rw-mediainfo programs.
+ On the other hand, we do not have enough information to ensure
+ that DVD-RW or other forms of DVDs work correctly.
+\item DVD+RW supports only about 1000 overwrites. Every time you
+ mount the filesystem read/write will count as one write. This can
+ add up quickly, so it is best to mount your DVD+RW filesystem read-only.
+ Bacula does not need the DVD to be mounted read-write, since it uses
+ the raw device for writing.
+\item Reformatting DVD+RW 10-20 times can apparently make the medium
+ unusable. Normally you should not have to format or reformat
+ DVD+RW media. If it is necessary, current versions of growisofs will
+ do so automatically.
+\item We have had several problems writing to DVD-RWs (this does NOT
+ concern DVD+RW), because these media have two writing-modes: {\bf
+ Incremental Sequential} and {\bf Restricted Overwrite}. Depending on
+ your device and the media you use, one of these modes may not work
+ correctly (e.g. {\bf Incremental Sequential} does not work with my NEC
+ DVD-writer and Verbatim DVD-RW).
+
+ To retrieve the current mode of a DVD-RW, run:
+\begin{verbatim}
+ dvd+rw-mediainfo /dev/xxx
+\end{verbatim}
+ where you replace xxx with your DVD device name.
+
+ {\bf Mounted Media} line should give you the information.
+
+ To set the device to {\bf Restricted Overwrite} mode, run:
+\begin{verbatim}
+ dvd+rw-format /dev/xxx
+\end{verbatim}
+ If you want to set it back to the default {\bf Incremental Sequential} mode, run:
+\begin{verbatim}
+ dvd+rw-format -blank /dev/xxx
+\end{verbatim}
+
+\item Bacula only accepts to write to blank DVDs. To quickly blank a DVD+/-RW, run
+ this command:
+\begin{verbatim}
+ dd if=/dev/zero bs=1024 count=512 | growisofs -Z /dev/xxx=/dev/fd/0
+\end{verbatim}
+ Then, try to mount the device, if it cannot be mounted, it will be considered
+ as blank by Bacula, if it can be mounted, try a full blank (see below).
+
+\item If you wish to blank completely a DVD+/-RW, use the following:
+\begin{verbatim}
+ growisofs -Z /dev/xxx=/dev/zero
+\end{verbatim}
+ where you replace xxx with your DVD device name. However, note that this
+ blanks the whole DVD, which takes quite a long time (16 minutes on mine).
+\item DVD+RW and DVD-RW support only about 1000 overwrites (i.e. don't use the
+same medium for years if you don't want to have problems...).
+
+\item For more informations about DVD writing, please look at the
+\elink{dvd+rw-tools homepage}{http://fy.chalmers.se/~appro/linux/DVD+RW/}.
+\end{itemize}
projects / bacula / docs / commitdiff
