5 \label{_DVDChapterStart}
6 \index[general]{DVD Volumes}
7 \index[general]{Writing DVDs}
8 \index[general]{DVD Writing}
9 \index[general]{Volumes!DVD}
11 Please note that the DVD code is depreciated, that is
12 we no longer support it, and in a future version it will
13 be removed. The code is very likely not to work.
15 The reason we have depreciated it is that writing to DVD
16 devices is not very reliable, and more modern devices
17 such as USB sticks or USB drives are much more reliable.
19 Just the same if you want to write Bacula Volumes to DVDs,
20 or CDs, you can do so by limiting the size of the Bacula
21 volume to be slightly smaller than the device, then when
22 you are ready, you simply write the volume to the DVD by
23 using any standard DVD burning program.
25 Bacula allows you to specify that you want to write to DVD. However,
26 this feature is implemented only in version 1.37 or later.
27 You may in fact write to DVD+RW, DVD+R, DVD-R, or DVD-RW
28 media. The actual process used by Bacula is to first write
29 the image to a spool directory, then when the Volume reaches
30 a certain size or, at your option, at the end of a Job, Bacula
31 will transfer the image from the spool directory to the
32 DVD. The actual work of transferring the image is done
33 by a script {\bf dvd-handler}, and the heart of that
34 script is a program called {\bf growisofs} which allows
35 creating or adding to a DVD ISO filesystem.
37 You must have {\bf dvd+rw-tools} loaded on your system for DVD writing to
38 work. Please note that the original {\bf dvd+rw-tools} package does {\bf
39 NOT} work with Bacula. You must apply a patch which can be found in the
40 {\bf patches} directory of Bacula sources with the name
41 {\bf dvd+rw-tools-5.21.4.10.8.bacula.patch} for version 5.21 of the tools,
42 or patch {bf dvd+rw-tools-6.1.bacula.patch} if you have version 6.1
43 on your system. Unfortunately, this requires you to build the dvd\_rw-tools
46 Note, some Linux distros such as Debian dvd+rw-tools-7.0-4 package already
47 have the patch applied, so please check.
49 The fact that Bacula cannot use the OS to write directly
50 to the DVD makes the whole process a bit more error prone than
51 writing to a disk or a tape, but nevertheless, it does work if you
52 use some care to set it up properly. However, at the current time
53 (version 1.39.30 -- 12 December 2006) we still consider this code to be
54 BETA quality. As a consequence, please do careful testing before relying
55 on DVD backups in production.
57 The remainder of this chapter explains the various directives that you can
58 use to control the DVD writing.
61 \section{DVD Specific SD Directives}
62 \index[general]{Directives!DVD}
63 \index[general]{DVD Specific SD Directives }
65 The following directives are added to the Storage daemon's
70 \item [Requires Mount = {\it Yes|No}]
71 \index[general]{Requires Mount }
72 You must set this directive to {\bf yes} for DVD-writers, and to {\bf no} for
73 all other devices (tapes/files). This directive indicates if the device
74 requires to be mounted using the {\bf Mount Command}.
75 To be able to write a DVD, the following directives must also be
76 defined: {\bf Mount Point}, {\bf Mount Command}, {\bf Unmount Command} and
77 {\bf Write Part Command}.
79 \item [Mount Point = {\it directory}]
80 \index[general]{Mount Point}
81 Directory where the device can be mounted.
83 \item [Mount Command = {\it name-string}]
84 \index[general]{Mount Command}
85 Command that must be executed to mount the device. Although the
86 device is written directly, the mount command is necessary in
87 order to determine the free space left on the DVD. Before the command is
88 executed, \%a is replaced with the Archive Device, and \%m with the Mount
91 Most frequently, you will define it as follows:
95 Mount Command = "/bin/mount -t iso9660 -o ro %a %m"
99 However, if you have defined a mount point in /etc/fstab, you might be
100 able to use a mount command such as:
104 Mount Command = "/bin/mount /media/dvd"
109 \item [Unmount Command = {\it name-string}]
110 \index[general]{Unmount Command}
111 Command that must be executed to unmount the device. Before the command is
112 executed, \%a is replaced with the Archive Device, and \%m with the Mount
115 Most frequently, you will define it as follows:
119 Unmount Command = "/bin/umount %m"
123 \item [Write Part Command = {\it name-string}]
124 \index[general]{Write Part Command }
125 Command that must be executed to write a part to the device. Before the
126 command is executed, \%a is replaced with the Archive Device, \%m with the
127 Mount Point, \%e is replaced with 1 if we are writing the first part,
128 and with 0 otherwise, and \%v with the current part filename.
130 For a DVD, you will most frequently specify the Bacula supplied {\bf
131 dvd-handler} script as follows:
135 Write Part Command = "/path/dvd-handler %a write %e %v"
139 Where {\bf /path} is the path to your scripts install directory, and
140 dvd-handler is the Bacula supplied script file.
141 This command will already be present, but commented out,
142 in the default bacula-sd.conf file. To use it, simply remove
143 the comment (\#) symbol.
146 \item [Free Space Command = {\it name-string}]
147 \index[general]{Free Space Command }
148 Command that must be executed to check how much free space is left on the
149 device. Before the command is executed,\%a is replaced with the Archive
152 For a DVD, you will most frequently specify the Bacula supplied {\bf
153 dvd-handler} script as follows:
157 Free Space Command = "/path/dvd-handler %a free"
161 Where {\bf /path} is the path to your scripts install directory, and
162 dvd-handler is the Bacula supplied script file.
163 If you want to specify your own command, please look at the code in
164 dvd-handler to see what output Bacula expects from this command.
165 This command will already be present, but commented out,
166 in the default bacula-sd.conf file. To use it, simply remove
167 the comment (\#) symbol.
169 If you do not set it, Bacula will expect there is always free space on the
174 In addition to the directives specified above, you must also
175 specify the other standard Device resource directives. Please see the
176 sample DVD Device resource in the default bacula-sd.conf file. Be sure
177 to specify the raw device name for {\bf Archive Device}. It should
178 be a name such as {\bf /dev/cdrom} or {\bf /media/cdrecorder} or
179 {\bf /dev/dvd} depending on your system. It will not be a name such
182 Finally, for {\bf growisofs} to work, it must be able to lock
183 a certain amount of memory in RAM. If you have restrictions on
184 this function, you may have failures. Under {\bf bash}, you can
185 set this with the following command:
193 \section{Edit Codes for DVD Directives}
194 \index[general]{Directives!DVD Edit Codes}
195 \index[general]{Edit Codes for DVD Directives }
197 Before submitting the {\bf Mount Command}, {\bf Unmount Command},
198 {\bf Write Part Command}, or {\bf Free Space Command} directives
199 to the operating system, Bacula performs character substitution of the
200 following characters:
205 %a = Archive device name
206 %e = erase (set if cannot mount and first part)
209 %v = last part name (i.e. filename)
215 \section{DVD Specific Director Directives}
216 \index[general]{Directives!DVD}
217 \index[general]{DVD Specific Director Directives }
219 The following directives are added to the Director's Job resource.
221 \label{WritePartAfterJob}
223 \item [Write Part After Job = \lt{}yes|no\gt{}]
224 \index[general]{Write Part After Job }
225 If this directive is set to {\bf yes} (default {\bf no}), the
226 Volume written to a temporary spool file for the current Job will
227 be written to the DVD as a new part file
228 will be created after the job is finished.
230 It should be set to {\bf yes} when writing to devices that require a mount
231 (for example DVD), so you are sure that the current part, containing
232 this job's data, is written to the device, and that no data is left in
233 the temporary file on the hard disk. However, on some media, like DVD+R
234 and DVD-R, a lot of space (about 10Mb) is lost everytime a part is
235 written. So, if you run several jobs each after another, you could set
236 this directive to {\bf no} for all jobs, except the last one, to avoid
237 wasting too much space, but to ensure that the data is written to the
238 medium when all jobs are finished.
240 This directive is ignored for devices other than DVDs.
246 \section{Other Points}
247 \index[general]{Points!Other }
248 \index[general]{Other Points }
251 \item Please be sure that you have any automatic DVD mounting
252 disabled before running Bacula -- this includes auto mounting
253 in /etc/fstab, hotplug, ... If the DVD is automatically
254 mounted by the OS, it will cause problems when Bacula tries
255 to mount/unmount the DVD.
256 \item Please be sure that you the directive {\bf Write Part After Job}
257 set to {\bf yes}, otherwise the last part of the data to be
258 written will be left in the DVD spool file and not written to
259 the DVD. The DVD will then be unreadable until this last part
260 is written. If you have a series of jobs that are run one at
261 a time, you can turn this off until the last job is run.
262 \item The current code is not designed to have multiple simultaneous
263 jobs writing to the DVD. As a consequence, please ensure that
264 only one DVD backup job runs at any time.
265 \item Writing and reading of DVD+RW seems to work quite reliably
266 provided you are using the patched dvd+rw-mediainfo programs.
267 On the other hand, we do not have enough information to ensure
268 that DVD-RW or other forms of DVDs work correctly.
269 \item DVD+RW supports only about 1000 overwrites. Every time you
270 mount the filesystem read/write will count as one write. This can
271 add up quickly, so it is best to mount your DVD+RW filesystem read-only.
272 Bacula does not need the DVD to be mounted read-write, since it uses
273 the raw device for writing.
274 \item Reformatting DVD+RW 10-20 times can apparently make the medium
275 unusable. Normally you should not have to format or reformat
276 DVD+RW media. If it is necessary, current versions of growisofs will
278 \item We have had several problems writing to DVD-RWs (this does NOT
279 concern DVD+RW), because these media have two writing-modes: {\bf
280 Incremental Sequential} and {\bf Restricted Overwrite}. Depending on
281 your device and the media you use, one of these modes may not work
282 correctly (e.g. {\bf Incremental Sequential} does not work with my NEC
283 DVD-writer and Verbatim DVD-RW).
285 To retrieve the current mode of a DVD-RW, run:
287 dvd+rw-mediainfo /dev/xxx
289 where you replace xxx with your DVD device name.
291 {\bf Mounted Media} line should give you the information.
293 To set the device to {\bf Restricted Overwrite} mode, run:
295 dvd+rw-format /dev/xxx
297 If you want to set it back to the default {\bf Incremental Sequential} mode, run:
299 dvd+rw-format -blank /dev/xxx
302 \item Bacula only accepts to write to blank DVDs. To quickly blank a DVD+/-RW, run
305 dd if=/dev/zero bs=1024 count=512 | growisofs -Z /dev/xxx=/dev/fd/0
307 Then, try to mount the device, if it cannot be mounted, it will be considered
308 as blank by Bacula, if it can be mounted, try a full blank (see below).
310 \item If you wish to blank completely a DVD+/-RW, use the following:
312 growisofs -Z /dev/xxx=/dev/zero
314 where you replace xxx with your DVD device name. However, note that this
315 blanks the whole DVD, which takes quite a long time (16 minutes on mine).
316 \item DVD+RW and DVD-RW support only about 1000 overwrites (i.e. don't use the
317 same medium for years if you don't want to have problems...).
319 To write to the DVD the first time use:
321 growisofs -Z /dev/xxx filename
324 To add additional files (more parts use):
327 growisofs -M /dev/xxx filename
330 The option {\bf -use-the-force-luke=4gms} was added in growisofs 5.20 to
331 override growisofs' behavior of always checking for the 4GB limit.
332 Normally, this option is recommended for all Linux 2.6.8 kernels or
333 greater, since these newer kernels can handle writing more than 4GB.
334 See below for more details on this subject.
336 \item For more information about DVD writing, please look at the
337 \elink{dvd+rw-tools homepage}{http://fy.chalmers.se/~appro/linux/DVD+RW/}.
339 \item According to bug \#912, bscan cannot read multi-volume DVDs. This is
340 on our TODO list, but unless someone submits a patch it is not likely to be
341 done any time in the near future. (9 Sept 2007).