4 \chapter{Autochanger Support}
5 \label{AutochangersChapter}
6 \index[general]{Support!Autochanger }
7 \index[general]{Autochanger Support }
9 Bacula provides autochanger support for reading and writing tapes. In
10 order to work with an autochanger, Bacula requires a number of things, each of
11 which is explained in more detail after this list:
14 \item A script that actually controls the autochanger according to commands
15 sent by Bacula. We furnish such a script that works with {\bf mtx} found in
16 the {\bf depkgs} distribution.
18 \item That each Volume (tape) to be used must be defined in the Catalog and
19 have a Slot number assigned to it so that Bacula knows where the Volume is
20 in the autochanger. This is generally done with the {\bf label} command, but
21 can also done after the tape is labeled using the {\bf update slots}
22 command. See below for more details. You must pre-label the tapes manually
25 \item Modifications to your Storage daemon's Device configuration resource to
26 identify that the device is a changer, as well as a few other parameters.
28 \item You should also modify your Storage resource definition in the
29 Director's configuration file so that you are automatically prompted for the
30 Slot when labeling a Volume.
32 \item You need to ensure that your Storage daemon (if not running as root)
33 has access permissions to both the tape drive and the control device.
35 \item You need to have {\bf Autochanger = yes} in your Storage resource
36 in your bacula-dir.conf file so that you will be prompted for the
37 slot number when you label Volumes.
40 In version 1.37 and later, there is a new \ilink{Autochanger
41 resource}{AutochangerRes} that permits you to group Device resources thus
42 creating a multi-drive autochanger. If you have an autochanger,
43 you {\bf must} use this new resource.
45 Bacula uses its own {\bf mtx-changer} script to interface with a program
46 that actually does the tape changing. Thus in principle, {\bf mtx-changer}
47 can be adapted to function with any autochanger program, or you can
48 call any other script or program. The current
49 version of {\bf mtx-changer} works with the {\bf mtx} program. However,
50 FreeBSD users have provided a script in the {\bf examples/autochangers}
51 directory that allows Bacula to use the {\bf chio} program.
53 Bacula also supports autochangers with barcode
54 readers. This support includes two Console commands: {\bf label barcodes}
55 and {\bf update slots}. For more details on these commands, see the "Barcode
56 Support" section below.
58 Current Bacula autochanger support does not include cleaning, stackers, or
59 silos. Stackers and silos are not supported because Bacula expects to
60 be able to access the Slots randomly.
61 However, if you are very careful to setup Bacula to access the Volumes
62 in the autochanger sequentially, you may be able to make Bacula
63 work with stackers (gravity feed and such).
65 Support for multi-drive
66 autochangers requires the \ilink{Autochanger resource}{AutochangerRes}
67 introduced in version 1.37. This resource is also recommended for single
70 In principle, if {\bf mtx} will operate your changer correctly, then it is
71 just a question of adapting the {\bf mtx-changer} script (or selecting one
72 already adapted) for proper interfacing. You can find a list of autochangers
73 supported by {\bf mtx} at the following link:
74 \elink{http://mtx.opensource-sw.net/compatibility.php}
75 {http://mtx.opensource-sw.net/compatibility.php}.
76 The home page for the {\bf mtx} project can be found at:
77 \elink{http://mtx.opensource-sw.net/}{http://mtx.opensource-sw.net/}.
79 Note, we have feedback from some users that there are certain
80 incompatibilities between the Linux kernel and mtx. For example between
81 kernel 2.6.18-8.1.8.el5 of CentOS and RedHat and version 1.3.10 and 1.3.11
82 of mtx. This was fixed by upgrading to a version 2.6.22 kernel.
84 In addition, apparently certain versions of mtx, for example, version
85 1.3.11 limit the number of slots to a maximum of 64. The solution was to
88 If you are having troubles, please use the {\bf auto} command in the {\bf
89 btape} program to test the functioning of your autochanger with Bacula. When
90 Bacula is running, please remember that for many distributions (e.g. FreeBSD,
91 Debian, ...) the Storage daemon runs as {\bf bacula.tape} rather than {\bf
92 root.root}, so you will need to ensure that the Storage daemon has sufficient
93 permissions to access the autochanger.
95 Some users have reported that the the Storage daemon blocks under certain
96 circumstances in trying to mount a volume on a drive that has a different
97 volume loaded. As best we can determine, this is simply a matter of
98 waiting a bit. The drive was previously in use writing a Volume, and
99 sometimes the drive will remain BLOCKED for a good deal of time (up to 7
100 minutes on a slow drive) waiting for the cassette to rewind and to unload
101 before the drive can be used with a different Volume.
104 \section{Knowing What SCSI Devices You Have}
105 \index[general]{Have!Knowing What SCSI Devices You }
106 \index[general]{Knowing What SCSI Devices You Have }
107 \index[general]{SCSI devices}
108 \index[general]{devices!SCSI}
118 to see what SCSI devices you have available. You can also:
122 cat /proc/scsi/sg/device_hdr /proc/scsi/sg/devices
126 to find out how to specify their control address ({\bf /dev/sg0} for the
127 first, {\bf /dev/sg1} for the second, ...) on the {\bf Changer Device = }
130 You can also use the excellent {\bf lsscsi} tool.
134 [1:0:2:0] tape SEAGATE ULTRIUM06242-XXX 1619 /dev/st0 /dev/sg9
135 [1:0:14:0] mediumx STK L180 0315 /dev/sch0 /dev/sg10
136 [2:0:3:0] tape HP Ultrium 3-SCSI G24S /dev/st1 /dev/sg11
137 [3:0:0:0] enclosu HP A6255A HP04 - /dev/sg3
138 [3:0:1:0] disk HP 36.4G ST336753FC HP00 /dev/sdd /dev/sg4
142 For more detailed information on what SCSI devices you have please see
143 the \ilink{Linux SCSI Tricks}{SCSITricks} section of the Tape Testing
144 chapter of this manual.
146 Under FreeBSD, you can use:
154 To list the SCSI devices as well as the {\bf /dev/passn} that you will use on
155 the Bacula {\bf Changer Device = } directive.
157 Please check that your Storage daemon has permission to access this
160 The following tip for FreeBSD users comes from Danny Butroyd:
161 on reboot Bacula will NOT have permission to
162 control the device /dev/pass0 (assuming this is your changer device).
163 To get around this just edit the /etc/devfs.conf file and add the
164 following to the bottom:
167 own pass0 root:bacula
169 own nsa0.0 root:bacula
174 This gives the bacula group permission to write to the nsa0.0 device
175 too just to be on the safe side. To bring these changes into effect
178 /etc/rc.d/devfs restart
180 Basically this will stop you having to manually change permissions on these
181 devices to make Bacula work when operating the AutoChanger after a reboot.
184 \section{Example Scripts}
185 \index[general]{Scripts!Example }
186 \index[general]{Example Scripts }
188 Please read the sections below so that you understand how autochangers work
189 with Bacula. Although we supply a default {\bf mtx-changer} script, your
190 autochanger may require some additional changes. If you want to see examples
191 of configuration files and scripts, please look in the {\bf
192 \lt{}bacula-src\gt{}/examples/devices} directory where you will find an
193 example {\bf HP-autoloader.conf} Bacula Device resource, and several {\bf
194 mtx-changer} scripts that have been modified to work with different
200 \index[general]{Slots }
202 To properly address autochangers, Bacula must know which Volume is in each
203 {\bf slot} of the autochanger. Slots are where the changer cartridges reside
204 when not loaded into the drive. Bacula numbers these slots from one to the
205 number of cartridges contained in the autochanger.
207 Bacula will not automatically use a Volume in your autochanger unless it is
208 labeled and the slot number is stored in the catalog and the Volume is marked
209 as InChanger. This is because it must know where each volume is (slot) to
210 be able to load the volume.
211 For each Volume in your
212 changer, you will, using the Console program, assign a slot. This information
213 is kept in {\bf Bacula's} catalog database along with the other data for the
214 volume. If no slot is given, or the slot is set to zero, Bacula will not
215 attempt to use the autochanger even if all the necessary configuration records
216 are present. When doing a {\bf mount} command on an autochanger, you must
217 specify which slot you want mounted. If the drive is loaded with a tape
218 from another slot, it will unload it and load the correct tape, but
219 normally, no tape will be loaded because an {\bf unmount} command causes
220 Bacula to unload the tape in the drive.
223 You can check if the Slot number and InChanger flag are set by doing a:
228 in the Console program.
231 \section{Multiple Devices}
232 \index[general]{Devices!Multiple}
233 \index[general]{Multiple Devices}
235 Some autochangers have more than one read/write device (drive). The
236 new \ilink{Autochanger resource}{AutochangerRes} introduced in version
237 1.37 permits you to group Device resources, where each device
238 represents a drive. The Director may still reference the Devices (drives)
239 directly, but doing so, bypasses the proper functioning of the
240 drives together. Instead, the Director (in the Storage resource)
241 should reference the Autochanger resource name. Doing so permits
242 the Storage daemon to ensure that only one drive uses the mtx-changer
243 script at a time, and also that two drives don't reference the
246 Multi-drive requires the use of the {\bf
247 Drive Index} directive in the Device resource of the Storage daemon's
248 configuration file. Drive numbers or the Device Index are numbered beginning
249 at zero, which is the default. To use the second Drive in an autochanger, you
250 need to define a second Device resource and set the Drive Index to 1 for
251 that device. In general, the second device will have the same {\bf Changer
252 Device} (control channel) as the first drive, but a different {\bf Archive
255 As a default, Bacula jobs will prefer to write to a Volume that is
256 already mounted. If you have a multiple drive autochanger and you want
257 Bacula to write to more than one Volume in the same Pool at the same
258 time, you will need to set \ilink{Prefer Mounted Volumes} {PreferMountedVolumes}
259 in the Directors Job resource to {\bf no}. This will cause
260 the Storage daemon to maximize the use of drives.
263 \label{ConfigRecords}
264 \section{Device Configuration Records}
265 \index[general]{Records!Device Configuration }
266 \index[general]{Device Configuration Records }
268 Configuration of autochangers within Bacula is done in the Device resource of
269 the Storage daemon. Four records: {\bf Autochanger}, {\bf Changer Device},
270 {\bf Changer Command}, and {\bf Maximum Changer Wait} control how Bacula uses
273 These four records, permitted in {\bf Device} resources, are described in
274 detail below. Note, however, that the {\bf Changer Device} and the
275 {\bf Changer Command} directives are not needed in the Device resource
276 if they are present in the {\bf Autochanger} resource.
280 \item [Autochanger = {\it Yes|No} ]
281 \index[sd]{Autochanger }
282 The {\bf Autochanger} record specifies that the current device is or is not
283 an autochanger. The default is {\bf no}.
285 \item [Changer Device = \lt{}device-name\gt{}]
286 \index[sd]{Changer Device }
287 In addition to the Archive Device name, you must specify a {\bf Changer
288 Device} name. This is because most autochangers are controlled through a
289 different device than is used for reading and writing the cartridges. For
290 example, on Linux, one normally uses the generic SCSI interface for
291 controlling the autochanger, but the standard SCSI interface for reading and
292 writing the tapes. On Linux, for the {\bf Archive Device = /dev/nst0}, you
293 would typically have {\bf Changer Device = /dev/sg0}. Note, some of the more
294 advanced autochangers will locate the changer device on {\bf /dev/sg1}. Such
295 devices typically have several drives and a large number of tapes.
297 On FreeBSD systems, the changer device will typically be on {\bf /dev/pass0}
298 through {\bf /dev/passn}.
300 On Solaris, the changer device will typically be some file under {\bf
303 Please ensure that your Storage daemon has permission to access this
306 \item [Changer Command = \lt{}command\gt{}]
307 \index[sd]{Changer Command }
308 This record is used to specify the external program to call and what
309 arguments to pass to it. The command is assumed to be a standard program or
310 shell script that can be executed by the operating system. This command is
311 invoked each time that Bacula wishes to manipulate the autochanger. The
312 following substitutions are made in the {\bf command} before it is sent to
313 the operating system for execution:
318 %a = archive device name
319 %c = changer device name
320 %d = changer drive index base 0
323 %o = command (loaded, load, or unload)
330 An actual example for using {\bf mtx} with the {\bf mtx-changer} script (part
331 of the Bacula distribution) is:
335 Changer Command = "/etc/bacula/mtx-changer %c %o %S %a %d"
339 Where you will need to adapt the {\bf /etc/bacula} to be the actual path on
340 your system where the mtx-changer script resides. Details of the three
341 commands currently used by Bacula (loaded, load, unload) as well as the
342 output expected by Bacula are give in the {\bf Bacula Autochanger Interface}
345 \item [Maximum Changer Wait = \lt{}time\gt{}]
346 \index[sd]{Maximum Changer Wait }
347 This record is used to define the maximum amount of time that Bacula
348 will wait for an autoloader to respond to a command (e.g. load). The
349 default is set to 120 seconds. If you have a slow autoloader you may
350 want to set it longer.
352 If the autoloader program fails to respond in this time, it will be killed
353 and Bacula will request operator intervention.
355 \item [Drive Index = \lt{}number\gt{}]
356 \index[sd]{Drive Index }
357 This record allows you to tell Bacula to use the second or subsequent
358 drive in an autochanger with multiple drives. Since the drives are
359 numbered from zero, the second drive is defined by
368 To use the second drive, you need a second Device resource definition in the
369 Bacula configuration file. See the Multiple Drive section above in this
370 chapter for more information.
373 In addition, for proper functioning of the Autochanger, you must
374 define an Autochanger resource.
375 \input{autochangerres}
378 \section{An Example Configuration File}
379 \index[general]{Example Configuration File }
380 \index[general]{File!Example Configuration }
382 The following two resources implement an autochanger:
389 Changer Device = /dev/sg0
390 Changer Command = "/etc/bacula/mtx-changer %c %o %S %a %d"
396 Archive Device = /dev/nst0 # Normal archive device
399 AutomaticMount = yes;
405 where you will adapt the {\bf Archive Device}, the {\bf Changer Device}, and
406 the path to the {\bf Changer Command} to correspond to the values used on your
409 \section{A Multi-drive Example Configuration File}
410 \index[general]{Multi-drive Example Configuration File }
412 The following resources implement a multi-drive autochanger:
418 Device = Drive-1, Drive-2
419 Changer Device = /dev/sg0
420 Changer Command = "/etc/bacula/mtx-changer %c %o %S %a %d"
427 Archive Device = /dev/nst0 # Normal archive device
430 AutomaticMount = yes;
438 Archive Device = /dev/nst1 # Normal archive device
441 AutomaticMount = yes;
448 where you will adapt the {\bf Archive Device}, the {\bf Changer Device}, and
449 the path to the {\bf Changer Command} to correspond to the values used on your
452 \label{SpecifyingSlots}
453 \section{Specifying Slots When Labeling}
454 \index[general]{Specifying Slots When Labeling }
455 \index[general]{Labeling!Specifying Slots When }
457 If you add an {\bf Autochanger = yes} record to the Storage resource in your
458 Director's configuration file, the Bacula Console will automatically prompt
459 you for the slot number when the Volume is in the changer when
460 you {\bf add} or {\bf label} tapes for that Storage device. If your
461 {\bf mtx-changer} script is properly installed, Bacula will automatically
462 load the correct tape during the label command.
465 {\bf Autochanger = yes} in the Storage daemon's Device resource
466 as we have described above in
467 order for the autochanger to be used. Please see the
468 \ilink{Storage Resource}{Autochanger1} in the Director's chapter
470 \ilink{Device Resource}{Autochanger} in the Storage daemon
471 chapter for more details on these records.
473 Thus all stages of dealing with tapes can be totally automated. It is also
474 possible to set or change the Slot using the {\bf update} command in the
475 Console and selecting {\bf Volume Parameters} to update.
477 Even though all the above configuration statements are specified and correct,
478 Bacula will attempt to access the autochanger only if a {\bf slot} is non-zero
479 in the catalog Volume record (with the Volume name).
481 If your autochanger has barcode labels, you can label all the Volumes in
482 your autochanger one after another by using the {\bf label barcodes} command.
483 For each tape in the changer containing a barcode, Bacula will mount the tape
484 and then label it with the same name as the barcode. An appropriate Media
485 record will also be created in the catalog. Any barcode that begins with the
486 same characters as specified on the "CleaningPrefix=xxx" command, will be
487 treated as a cleaning tape, and will not be labeled. For example with:
489 Please note that Volumes must be pre-labeled to be automatically used in
490 the autochanger during a backup. If you do not have a barcode reader, this
491 is done manually (or via a script).
497 Cleaning Prefix = "CLN"
502 Any slot containing a barcode of CLNxxxx will be treated as a cleaning tape
503 and will not be mounted.
505 \section{Changing Cartridges}
506 \index[general]{Changing Cartridges }
507 If you wish to insert or remove cartridges in your autochanger or
508 you manually run the {\bf mtx} program, you must first tell Bacula
509 to release the autochanger by doing:
514 (change cartridges and/or run mtx)
519 If you do not do the unmount before making such a change, Bacula
520 will become completely confused about what is in the autochanger
521 and may stop function because it expects to have exclusive use
522 of the autochanger while it has the drive mounted.
526 \section{Dealing with Multiple Magazines}
527 \index[general]{Dealing with Multiple Magazines }
528 \index[general]{Magazines!Dealing with Multiple }
530 If you have several magazines or if you insert or remove cartridges from a
531 magazine, you should notify Bacula of this. By doing so, Bacula will as
532 a preference, use Volumes that it knows to be in the autochanger before
533 accessing Volumes that are not in the autochanger. This prevents unneeded
534 operator intervention.
536 If your autochanger has barcodes (machine readable tape labels), the task of
537 informing Bacula is simple. Every time, you change a magazine, or add or
538 remove a cartridge from the magazine, simply do
544 (insert new magazine)
550 in the Console program. This will cause Bacula to request the autochanger to
551 return the current Volume names in the magazine. This will be done without
552 actually accessing or reading the Volumes because the barcode reader does this
553 during inventory when the autochanger is first turned on. Bacula will ensure
554 that any Volumes that are currently marked as being in the magazine are marked
555 as no longer in the magazine, and the new list of Volumes will be marked as
556 being in the magazine. In addition, the Slot numbers of the Volumes will be
557 corrected in Bacula's catalog if they are incorrect (added or moved).
559 If you do not have a barcode reader on your autochanger, you have several
563 \item You can manually set the Slot and InChanger flag using the {\bf update
564 volume} command in the Console (quite painful).
566 \item You can issue a
574 command that will cause Bacula to read the label on each of the cartridges in
575 the magazine in turn and update the information (Slot, InChanger flag) in the
576 catalog. This is quite effective but does take time to load each cartridge
577 into the drive in turn and read the Volume label.
579 \item You can modify the mtx-changer script so that it simulates an
580 autochanger with barcodes. See below for more details.
584 \section{Simulating Barcodes in your Autochanger}
585 \index[general]{Autochanger!Simulating Barcodes in your }
586 \index[general]{Simulating Barcodes in your Autochanger }
588 You can simulate barcodes in your autochanger by making the {\bf mtx-changer}
589 script return the same information that an autochanger with barcodes would do.
590 This is done by commenting out the one and only line in the {\bf list)} case,
595 ${MTX} -f $ctl status | grep " *Storage Element [0-9]*:.*Full" | awk "{print \$3 \$4}" | sed "s/Full *\(:VolumeTag=\)*//"
599 at approximately line 99 by putting a \# in column one of that line, or by
600 simply deleting it. Then in its place add a new line that prints the contents
601 of a file. For example:
605 cat /etc/bacula/changer.volumes
609 Be sure to include a full path to the file, which can have any name. The
610 contents of the file must be of the following format:
621 Where the 1, 2, 3 are the slot numbers and Volume1, Volume2, ... are the
622 Volume names in those slots. You can have multiple files that represent the
623 Volumes in different magazines, and when you change magazines, simply copy the
624 contents of the correct file into your {\bf /etc/bacula/changer.volumes} file.
625 There is no need to stop and start Bacula when you change magazines, simply
626 put the correct data in the file, then run the {\bf update slots} command, and
627 your autochanger will appear to Bacula to be an autochanger with barcodes.
630 \section{The Full Form of the Update Slots Command}
631 \index[general]{Full Form of the Update Slots Command }
632 \index[general]{Command!Full Form of the Update Slots }
634 If you change only one cartridge in the magazine, you may not want to scan all
635 Volumes, so the {\bf update slots} command (as well as the {\bf update slots
636 scan} command) has the additional form:
640 update slots=n1,n2,n3-n4, ...
644 where the keyword {\bf scan} can be appended or not. The n1,n2, ... represent
645 Slot numbers to be updated and the form n3-n4 represents a range of Slot
646 numbers to be updated (e.g. 4-7 will update Slots 4,5,6, and 7).
648 This form is particularly useful if you want to do a scan (time expensive) and
649 restrict the update to one or two slots.
651 For example, the command:
655 update slots=1,6 scan
659 will cause Bacula to load the Volume in Slot 1, read its Volume label and
660 update the Catalog. It will do the same for the Volume in Slot 6. The command:
669 will read the barcoded Volume names for slots 1,2,3 and 6 and make the
670 appropriate updates in the Catalog. If you don't have a barcode reader or have
671 not modified the mtx-changer script as described above, the above command will
672 not find any Volume names so will do nothing.
675 \section{FreeBSD Issues}
676 \index[general]{Issues!FreeBSD }
677 \index[general]{FreeBSD Issues }
679 If you are having problems on FreeBSD when Bacula tries to select a tape, and
680 the message is {\bf Device not configured}, this is because FreeBSD has made
681 the tape device {\bf /dev/nsa1} disappear when there is no tape mounted in the
682 autochanger slot. As a consequence, Bacula is unable to open the device. The
683 solution to the problem is to make sure that some tape is loaded into the tape
684 drive before starting Bacula. This problem is corrected in Bacula versions
688 \ilink{ Tape Testing}{FreeBSDTapes} chapter of this manual for
689 {\bf important} information concerning your tape drive before doing the
691 \label{AutochangerTesting}
693 \section{Testing Autochanger and Adapting mtx-changer script}
694 \index[general]{Testing the Autochanger }
695 \index[general]{Adapting Your mtx-changer script}
698 Before attempting to use the autochanger with Bacula, it is preferable to
699 "hand-test" that the changer works. To do so, we suggest you do the
700 following commands (assuming that the {\bf mtx-changer} script is installed in
701 {\bf /etc/bacula/mtx-changer}):
705 \item [Make sure Bacula is not running.]
707 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ list \ 0 \ /dev/nst0 \ 0]
708 \index[sd]{mtx-changer list}
710 This command should print:
722 or one number per line for each slot that is occupied in your changer, and
723 the number should be terminated by a colon ({\bf :}). If your changer has
724 barcodes, the barcode will follow the colon. If an error message is printed,
725 you must resolve the problem (e.g. try a different SCSI control device name
726 if {\bf /dev/sg0} is incorrect). For example, on FreeBSD systems, the
727 autochanger SCSI control device is generally {\bf /dev/pass2}.
729 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ slots ]
730 \index[sd]{mtx-changer slots}
732 This command should return the number of slots in your autochanger.
734 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ unload \ 1 \ /dev/nst0 \ 0 ]
735 \index[sd]{mtx-changer unload}
737 If a tape is loaded from slot 1, this should cause it to be unloaded.
739 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ load \ 3 \ /dev/nst0 \ 0 ]
740 \index[sd]{mtx-changer load}
742 Assuming you have a tape in slot 3, it will be loaded into drive (0).
745 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ loaded \ 0 \ /dev/nst0 \ 0]
746 \index[sd]{mtx-changer loaded}
749 Note, we have used an "illegal" slot number 0. In this case, it is simply
750 ignored because the slot number is not used. However, it must be specified
751 because the drive parameter at the end of the command is needed to select
754 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ unload \ 3 /dev/nst0 \ 0]
756 will unload the tape into slot 3.
760 Once all the above commands work correctly, assuming that you have the right
761 {\bf Changer Command} in your configuration, Bacula should be able to operate
762 the changer. The only remaining area of problems will be if your autoloader
763 needs some time to get the tape loaded after issuing the command. After the
764 {\bf mtx-changer} script returns, Bacula will immediately rewind and read the
765 tape. If Bacula gets rewind I/O errors after a tape change, you will probably
766 need to insert a {\bf sleep 20} after the {\bf mtx} command, but be careful to
767 exit the script with a zero status by adding {\bf exit 0} after any additional
768 commands you add to the script. This is because Bacula checks the return
769 status of the script, which should be zero if all went well.
771 You can test whether or not you need a {\bf sleep} by putting the following
772 commands into a file and running it as a script:
777 /etc/bacula/mtx-changer /dev/sg0 unload 1 /dev/nst0 0
778 /etc/bacula/mtx-changer /dev/sg0 load 3 /dev/nst0 0
779 mt -f /dev/st0 rewind
784 If the above script runs, you probably have no timing problems. If it does not
785 run, start by putting a {\bf sleep 30} or possibly a {\bf sleep 60} in the
786 script just after the mtx-changer load command. If that works, then you should
787 move the sleep into the actual {\bf mtx-changer} script so that it will be
788 effective when Bacula runs.
790 A second problem that comes up with a small number of autochangers is that
791 they need to have the cartridge ejected before it can be removed. If this is
792 the case, the {\bf load 3} will never succeed regardless of how long you wait.
793 If this seems to be your problem, you can insert an eject just after the
794 unload so that the script looks like:
799 /etc/bacula/mtx-changer /dev/sg0 unload 1 /dev/nst0 0
800 mt -f /dev/st0 offline
801 /etc/bacula/mtx-changer /dev/sg0 load 3 /dev/nst0 0
802 mt -f /dev/st0 rewind
807 Obviously, if you need the {\bf offline} command, you should move it into the
808 mtx-changer script ensuring that you save the status of the {\bf mtx} command
809 or always force an {\bf exit 0} from the script, because Bacula checks the
810 return status of the script.
812 As noted earlier, there are several scripts in {\bf
813 \lt{}bacula-source\gt{}/examples/devices} that implement the above features,
814 so they may be a help to you in getting your script to work.
816 If Bacula complains "Rewind error on /dev/nst0. ERR=Input/output error." you
817 most likely need more sleep time in your {\bf mtx-changer} before returning to
818 Bacula after a load command has been completed.
822 \section{Using the Autochanger}
823 \index[general]{Using the Autochanger }
824 \index[general]{Autochanger!Using the }
826 Let's assume that you have properly defined the necessary Storage daemon
827 Device records, and you have added the {\bf Autochanger = yes} record to the
828 Storage resource in your Director's configuration file.
830 Now you fill your autochanger with say six blank tapes.
832 What do you do to make Bacula access those tapes?
834 One strategy is to prelabel each of the tapes. Do so by starting Bacula, then
835 with the Console program, enter the {\bf label} command:
840 Connecting to Director rufus:8101
841 1000 OK: rufus-dir Version: 1.26 (4 October 2002)
846 it will then print something like:
850 Using default Catalog name=BackupDB DB=bacula
851 The defined Storage resources are:
854 Select Storage resource (1-2): 1
858 I select the autochanger (1), and it prints:
862 Enter new Volume name: TestVolume1
863 Enter slot (0 for none): 1
867 where I entered {\bf TestVolume1} for the tape name, and slot {\bf 1} for the
875 Select the Pool (1-2): 1
879 I select the Default pool. This will be automatically done if you only have a
880 single pool, then Bacula will proceed to unload any loaded volume, load the
881 volume in slot 1 and label it. In this example, nothing was in the drive, so
886 Connecting to Storage daemon Autochanger at localhost:9103 ...
887 Sending label command ...
888 3903 Issuing autochanger "load slot 1" command.
889 3000 OK label. Volume=TestVolume1 Device=/dev/nst0
890 Media record for Volume=TestVolume1 successfully created.
891 Requesting mount Autochanger ...
892 3001 Device /dev/nst0 is mounted with Volume TestVolume1
898 You may then proceed to label the other volumes. The messages will change
899 slightly because Bacula will unload the volume (just labeled TestVolume1)
900 before loading the next volume to be labeled.
902 Once all your Volumes are labeled, Bacula will automatically load them as they
905 To "see" how you have labeled your Volumes, simply enter the {\bf list
906 volumes} command from the Console program, which should print something like
912 Using default Catalog name=BackupDB DB=bacula
916 Select the Pool (1-2): 1
917 +-------+----------+--------+---------+-------+--------+----------+-------+------+
918 | MedId | VolName | MedTyp | VolStat | Bites | LstWrt | VolReten | Recyc | Slot |
919 +-------+----------+--------+---------+-------+--------+----------+-------+------+
920 | 1 | TestVol1 | DDS-4 | Append | 0 | 0 | 30672000 | 0 | 1 |
921 | 2 | TestVol2 | DDS-4 | Append | 0 | 0 | 30672000 | 0 | 2 |
922 | 3 | TestVol3 | DDS-4 | Append | 0 | 0 | 30672000 | 0 | 3 |
924 +-------+----------+--------+---------+-------+--------+----------+-------+------+
930 \section{Barcode Support}
931 \index[general]{Support!Barcode }
932 \index[general]{Barcode Support }
934 Bacula provides barcode support with two Console commands, {\bf label
935 barcodes} and {\bf update slots}.
937 The {\bf label barcodes} will cause Bacula to read the barcodes of all the
938 cassettes that are currently installed in the magazine (cassette holder) using
939 the {\bf mtx-changer} {\bf list} command. Each cassette is mounted in turn and
940 labeled with the same Volume name as the barcode.
942 The {\bf update slots} command will first obtain the list of cassettes and
943 their barcodes from {\bf mtx-changer}. Then it will find each volume in turn
944 in the catalog database corresponding to the barcodes and set its Slot to
945 correspond to the value just read. If the Volume is not in the catalog, then
946 nothing will be done. This command is useful for synchronizing Bacula with the
947 current magazine in case you have changed magazines or in case you have moved
948 cassettes from one slot to another. If the autochanger is empty, nothing will
951 The {\bf Cleaning Prefix} statement can be used in the Pool resource to define
952 a Volume name prefix, which if it matches that of the Volume (barcode) will
953 cause that Volume to be marked with a VolStatus of {\bf Cleaning}. This will
954 prevent Bacula from attempting to write on the Volume.
956 \section{Use bconsole to display Autochanger content}
958 The {\bf status slots storage=xxx} command displays autochanger content.
962 Slot | Volume Name | Status | Type | Pool | Loaded |
963 ------+-----------------+----------+-------------------+----------------+---------|
964 1 | 00001 | Append | DiskChangerMedia | Default | 0 |
965 2 | 00002 | Append | DiskChangerMedia | Default | 0 |
966 3*| 00003 | Append | DiskChangerMedia | Scratch | 0 |
971 If you see a {\bf *} near the slot number, you have to run {\bf update slots}
972 command to synchronize autochanger content with your catalog.
976 \section{Bacula Autochanger Interface}
977 \index[general]{Interface!Bacula Autochanger }
978 \index[general]{Bacula Autochanger Interface }
980 Bacula calls the autochanger script that you specify on the {\bf Changer
981 Command} statement. Normally this script will be the {\bf mtx-changer} script
982 that we provide, but it can in fact be any program. The only requirement
983 for the script is that it must understand the commands that
984 Bacula uses, which are {\bf loaded}, {\bf load}, {\bf
985 unload}, {\bf list}, and {\bf slots}. In addition,
986 each of those commands must return the information in the precise format as
991 - Currently the changer commands used are:
992 loaded -- returns number of the slot that is loaded, base 1,
993 in the drive or 0 if the drive is empty.
994 load -- loads a specified slot (note, some autochangers
995 require a 30 second pause after this command) into
997 unload -- unloads the device (returns cassette to its slot).
998 list -- returns one line for each cassette in the autochanger
999 in the format <slot>:<barcode>. Where
1000 the {\bf slot} is the non-zero integer representing
1001 the slot number, and {\bf barcode} is the barcode
1002 associated with the cassette if it exists and if you
1003 autoloader supports barcodes. Otherwise the barcode
1005 slots -- returns total number of slots in the autochanger.
1009 Bacula checks the exit status of the program called, and if it is zero, the
1010 data is accepted. If the exit status is non-zero, Bacula will print an
1011 error message and request the tape be manually mounted on the drive.