5 \label{_DVDChapterStart}
6 \index[general]{DVD Volumes}
7 \index[general]{Writing DVDs}
8 \index[general]{DVD Writing}
9 \index[general]{Volumes!DVD}
10 \addcontentsline{toc}{section}{DVD Volumes}
12 Bacula allows you to specify that you want to write to DVD. However,
13 this feature is implemented only in version 1.37 or later.
14 You may in fact write to DVD+RW, DVD+R, DVD-R, or DVD-RW
15 media. The actual process used by Bacula is to first write
16 the image to a spool directory, then when the Volume reaches
17 a certain size or, at your option, at the end of a Job, Bacula
18 will transfer the image from the spool directory to the
19 DVD. The actual work of transferring the image is done
20 by a script {\bf dvd-writepart}, and the heart of that
21 script is a program called {\bf growisofs} which allows
22 creating or adding to a DVD ISO filesystem. growisofs is
23 normally found in the {\bf dvd+rw-tools} package or rpm.
24 You must have it loaded on your system for DVD writing to
27 The fact that Bacula cannot use the OS to write directly
28 to the DVD makes the whole process a bit more error prone than
29 writing to say a disk, but nevertheless, it does work if you
30 use some care to set it up properly.
32 The remainder of this chapter explains the various directives that you can
33 use to control the DVD writing.
37 \subsection*{DVD Specific SD Directives}
38 \index[general]{Directives!DVD}
39 \index[general]{DVD Specific SD Directives }
40 \addcontentsline{toc}{subsection}{DVD Specific SD Directives}
42 The following directives are added to the Storage daemon's
47 \item [Requires Mount = {\it Yes|No}]
48 \index[sd]{Requires Mount }
49 You must set this directive to {\bf yes} for DVD-writers, and to {\bf no} for
50 all other devices (tapes/files). This directive indicates if the device
51 requires to be mounted to be read, and if it must be written in a special way.
52 If it set, {\bf Mount Point}, {\bf Mount Command}, {\bf Unmount Command} and
53 {\bf Write Part Command} directives must also be defined.
55 \item [Mount Point = {\it directory}]
56 \index[sd]{Mount Point }
57 Directory where the device can be mounted.
59 \item [Mount Command = {\it name-string}]
60 \index[sd]{Mount Command }
61 Command that must be executed to mount the device. Although the
62 device is written directly, the mount command is necessary in
63 order to determine the free space left on the DVD. Before the command is
64 executed, \%a is replaced with the Archive Device, and \%m with the Mount
67 Most frequently, you will define it as follows:
71 Mount Command = "/bin/mount -t iso9660 -o ro %a %m"
75 \item [Unmount Command = {\it name-string}]
76 \index[sd]{Unmount Command }
77 Command that must be executed to unmount the device. Before the command is
78 executed, \%a is replaced with the Archive Device, and \%m with the Mount
81 Most frequently, you will define it as follows:
85 Unmount Command = "/bin/umount %m"
89 \item [Write Part Command = {\it name-string}]
90 \index[sd]{Write Part Command }
91 Command that must be executed to write a part to the device. Before the
92 command is executed, \%a is replaced with the Archive Device, \%m with the
93 Mount Point, \%e is replaced with 1 if we are writing the first part,
94 and with 0 otherwise, and \%v with the current part filename.
96 For a DVD, you will most frequently specify the Bacula supplied {\bf
97 dvd-writepart} script as follows:
101 Write Part Command = "/path/dvd-writepart %e %a %v"
105 Where {\bf /path} is the path to your scripts install directory, and
106 dvd-writepart is the Bacula supplied script file.
107 This command will already be present, but commented out,
108 in the default bacula-sd.conf file. To use it, simply remove
109 the comment (\#) symbol.
112 \item [Free Space Command = {\it name-string}]
113 \index[sd]{Free Space Command }
114 Command that must be executed to check how much free space is left on the
115 device. Before the command is executed,\%a is replaced with the Archive
116 Device, \%m with the Mount Point, \%e is replaced with 1 if we are writing
117 the first part, and with 0 otherwise, and \%v with the current part filename.
119 For a DVD, you will most frequently specify the Bacula supplied {\bf
120 dvd-freespace} script as follows:
124 Free Space Command = "/path/dvd-freespace %a"
128 Where {\bf /path} is the path to your scripts install directory, and
129 dvd-freespace is the Bacula supplied script file.
130 If you want to specify your own command, please look at the code in
131 dvd-freespace to see what output Bacula expects from this command.
132 This command will already be present, but commented out,
133 in the default bacula-sd.conf file. To use it, simply remove
134 the comment (\#) symbol.
136 If you do not set it, Bacula will expect there is always free space on the
141 In addition to the directives specified above, you must also
142 specify the other standard Device resource directives. Please see the
143 sample DVD Device resource in the default bacula-sd.conf file. Be sure
144 to specify the raw device name for {\bf Archive Device}. It should
145 be a name such as {\bf /dev/cdrom} or {\bf /media/cdrecorder} or
146 {\bf /dev/dvd} depending on your system. It will not be a name such
150 \subsection*{DVD Specific Director Directives}
151 \index[general]{Directives!DVD}
152 \index[general]{DVD Specific Director Directives }
153 \addcontentsline{toc}{subsection}{DVD Specific Director Directives}
155 The following directives are added to the Director's Job resource.
157 \label{WritePartAfterJob}
159 \item [Write Part After Job = \lt{}yes|no\gt{}]
160 \index[dir]{Write Part After Job }
161 If this directive is set to {\bf yes} (default {\bf no}), the
162 Volume written to a temporary spool file for the current Job will
163 be written to the DVD as a new part file
164 will be created after the job is finished.
166 It should be set to {\bf yes} when writing to devices that require a mount
167 (for example DVD), so you are sure that the current part, containing
168 this job's data, is written to the device, and that no data is left in
169 the temporary file on the hard disk. However, on some media, like DVD+R
170 and DVD-R, a lot of space (about 10Mb) is lost everytime a part is
171 written. So, if you run several jobs each after another, you could set
172 this directive to {\bf no} for all jobs, except the last one, to avoid
173 wasting too much space, but to ensure that the data is written to the
174 medium when all jobs are finished.
176 It is ignored with tape and FIFO devices.
182 \subsection*{Other Points}
183 \index[general]{Points!Other }
184 \index[general]{Other Points }
185 \addcontentsline{toc}{subsection}{Other Points}
188 \item DVD+RW supports only about 1000 overwrites. Every time you
189 mount the filesystem read/write will count as one write. This can
190 add up quickly, so it is best to mount your DVD+RW filesystem read-only.
191 Bacula does not need the DVD to be mounted read-write, since it uses
192 the raw device for writing.
193 \item Reformatting DVD+RW 10-20 times can apparently make the medium
194 unusable. Normally you should not have to format or reformat
195 DVD+RW media. If it is necessary, current versions of growisofs will
197 \item I had several problems writing to DVD-RWs (this does NOT concern DVD+RW),
198 because these media have two writing-modes: {\bf Incremental Sequential} and
199 {\bf Restricted Overwrite}. Depending on your device and the media you use,
200 one of these modes may not work correctly (e.g. {\bf Incremental Sequential} does
201 not work with my NEC DVD-writer and Verbatim DVD-RW).
203 To retrieve the current mode of a DVD-RW, run:
205 dvd+rw-mediainfo /dev/xxx
207 where you replace xxx with your DVD device name.
209 {\bf Mounted Media} line should give you the information.
211 To set the device to {\bf Restricted Overwrite} mode, run:
213 dvd+rw-format /dev/xxx
215 If you want to set it back to the default {\bf Incremental Sequential} mode, run:
217 dvd+rw-format -blank /dev/xxx
220 \item Bacula only accepts to write to blank DVDs. To quick blank a DVD+/-RW, run
223 dd if=/dev/zero bs=1024 count=512 | growisofs -Z /dev/xxx=/dev/fd/0
225 Then, try to mount the device, if it cannot be mounted, it will be considered
226 as blank by Bacula, if it can be mounted, try a full blank (see below).
228 \item If you wish to blank completely a DVD+/-RW, use the following:
230 growisofs -Z /dev/xxx=/dev/zero
232 where you replace xxx with your DVD device name. However, note that this
233 blanks the whole DVD, which takes quite a long time (16 minutes on mine).
234 \item DVD+RW and DVD-RW support only about 1000 overwrites (i.e. don't use the
235 same medium for years if you don't want to have problems...).
237 \item For more informations about DVD writing, please look at the
238 \elink{dvd+rw-tools homepage}{http://fy.chalmers.se/~appro/linux/DVD+RW/}.