%%
%%
-\section*{DVD Volumes}
+\chapter{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.
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-writepart}, and the heart of that
+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. growisofs is
-normally found in the {\bf dvd+rw-tools} package or rpm.
-You must have it loaded on your system for DVD writing to
-work.
+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} for version 5.21 of the tools,
+or patch {bf dvd+rw-tools-6.1.bacula.patch} if you have version 6.1
+on your system. Unfortunately, this requires you to build the dvd\_rw-tools
+from source.
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 say a disk, but nevertheless, it does work if you
-use some care to set it up properly.
+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
+(version 1.39.30 -- 12 December 2006) we still consider this code to be
+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}
+\section{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.
\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 to be read, and if it must be written in a special way.
- If it set, {\bf Mount Point}, {\bf Mount Command}, {\bf Unmount Command} and
- {\bf Write Part Command} directives must also be defined.
+ 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 }
+ \index[sd]{Mount Point}
Directory where the device can be mounted.
\item [Mount Command = {\it name-string}]
- \index[sd]{Mount Command }
+ \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
\end{verbatim}
\normalsize
+However, if you have defined a mount point in /etc/fstab, you might be
+able to use a mount command such as:
+
+\footnotesize
+\begin{verbatim}
+ Mount Command = "/bin/mount /media/dvd"
+\end{verbatim}
+\normalsize
+
+
\item [Unmount Command = {\it name-string}]
- \index[sd]{Unmount Command }
+ \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.
\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, \%n with the current part number (0-based), and \%v with the
- current part filename.
+ 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-writepart} script as follows:
+ dvd-handler} script as follows:
\footnotesize
\begin{verbatim}
- Write Part Command = "/path/dvd-writepart %n %a %v"
+ 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-writepart is the Bacula supplied script file.
+ 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.
+ 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, \%n with the current part number (0-based),
- and \%v with the current part filename.
+ device. Before the command is executed,\%a is replaced with the Archive
+ Device.
For a DVD, you will most frequently specify the Bacula supplied {\bf
- dvd-freespace} script as follows:
+ dvd-handler} script as follows:
\footnotesize
\begin{verbatim}
- Free Space Command = "/path/dvd-freespace %n %a"
+ 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-freespace to see what output Bacula expects from this command.
+ 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.
+ the comment (\#) symbol.
If you do not set it, Bacula will expect there is always free space on the
device.
{\bf /dev/dvd} depending on your system. It will not be a name such
as {\bf /mnt/cdrom}.
+Finally, for {\bf growisofs} to work, it must be able to lock
+a certain amount of memory in RAM. If you have restrictions on
+this function, you may have failures. Under {\bf bash}, you can
+set this with the following command:
+
+\footnotesize
+\begin{verbatim}
+ulimit -l unlimited
+\end{verbatim}
+\normalsize
+
+\section{Edit Codes for DVD Directives}
+\index[general]{Directives!DVD Edit Codes}
+\index[general]{Edit Codes for DVD Directives }
+
+Before submitting the {\bf Mount Command}, {\bf Unmount Command},
+{\bf Write Part Command}, or {\bf Free Space Command} directives
+to the operating system, Bacula performs character substitution of the
+following characters:
+
+\footnotesize
+\begin{verbatim}
+ %% = %
+ %a = Archive device name
+ %e = erase (set if cannot mount and first part)
+ %n = part number
+ %m = mount point
+ %v = last part name (i.e. filename)
+\end{verbatim}
+\normalsize
+
-\subsection*{DVD Specific Director Directives}
+
+\section{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
wasting too much space, but to ensure that the data is written to the
medium when all jobs are finished.
- It is ignored with tape and FIFO devices.
+ This directive is ignored for devices other than DVDs.
\end{description}
\label{DVDpoints}
-\subsection*{Other Points}
+\section{Other Points}
\index[general]{Points!Other }
\index[general]{Other Points }
-\addcontentsline{toc}{subsection}{Other Points}
\begin{itemize}
-\item DVD+RW supports only about 1000 overwrites, so every time you
+\item Please be sure that you have any automatic DVD mounting
+ disabled before running Bacula -- this includes auto mounting
+ in /etc/fstab, hotplug, ... If the DVD is automatically
+ mounted by the OS, it will cause problems when Bacula tries
+ to mount/unmount the DVD.
+\item Please be sure that you the directive {\bf Write Part After Job}
+ set to {\bf yes}, otherwise the last part of the data to be
+ written will be left in the DVD spool file and not written to
+ the DVD. The DVD will then be unreadable until this last part
+ is written. If you have a series of jobs that are run one at
+ a time, you can turn this off until the last job is run.
+\item The current code is not designed to have multiple simultaneous
+ jobs writing to the DVD. As a consequence, please ensure that
+ only one DVD backup job runs at any time.
+\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.
-\item Reformating DVD+RW 10-20 time can apparently make the medium
+ 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 If you wish to blank your DVD, use the following:
+\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}
- growisofs -Z /dev/xxx=/dev/zero
+ 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...).
+
+To write to the DVD the first time use:
+\begin{verbatim}
+ growisofs -Z /dev/xxx filename
+\end{verbatim}
+
+To add additional files (more parts use):
+
+\begin{verbatim}
+ growisofs -M /dev/xxx filename
+\end{verbatim}
+
+The option {\bf -use-the-force-luke=4gms} was added in growisofs 5.20 to
+override growisofs' behavior of always checking for the 4GB limit.
+Normally, this option is recommended for all Linux 2.6.8 kernels or
+greater, since these newer kernels can handle writing more than 4GB.
+See below for more details on this subject.
+
+\item For more information 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 / blobdiff