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 resource}{AutochangerRes} that permits you to group Device resources thus
41 creating a multi-drive autochanger. If you have an autochanger,
42 you {\bf must} use this new resource.
44 Bacula uses its own {\bf mtx-changer} script to interface with a program
45 that actually does the tape changing. Thus in principle, {\bf mtx-changer}
46 can be adapted to function with any autochanger program, or you can
47 call any other script or program. The current
48 version of {\bf mtx-changer} works with the {\bf mtx} program. However,
49 FreeBSD users have provided a script in the {\bf examples/autochangers}
50 directory that allows Bacula to use the {\bf chio} program.
52 Bacula also supports autochangers with barcode
53 readers. This support includes two Console commands: {\bf label barcodes}
54 and {\bf update slots}. For more details on these commands, see the "Barcode
55 Support" section below.
57 Current Bacula autochanger support does not include cleaning, stackers, or
58 silos. Stackers and silos are not supported because Bacula expects to
59 be able to access the Slots randomly.
60 However, if you are very careful to setup Bacula to access the Volumes
61 in the autochanger sequentially, you may be able to make Bacula
62 work with stackers (gravity feed and such).
64 Support for multi-drive
65 autochangers requires the \ilink{Autochanger resource}{AutochangerRes}
66 introduced in version 1.37. This resource is also recommended for single
69 In principle, if {\bf mtx} will operate your changer correctly, then it is
70 just a question of adapting the {\bf mtx-changer} script (or selecting one
71 already adapted) for proper interfacing. You can find a list of autochangers
72 supported by {\bf mtx} at the following link:
73 \elink{http://mtx.opensource-sw.net/compatibility.php}{http://mtx.opensource-sw.net/compatibility.php}.
74 The home page for the {\bf mtx} project can be found at:
75 \elink{http://mtx.opensource-sw.net/}{http://mtx.opensource-sw.net/}.
77 Note, we have feedback from some users that there are certain
78 incompatibilities between the Linux kernel and mtx. For example between
79 kernel 2.6.18-8.1.8.el5 of CentOS and RedHat and version 1.3.10 and 1.3.11
80 of mtx. This was fixed by upgrading to a version 2.6.22 kernel.
82 In addition, apparently certain versions of mtx, for example, version
83 1.3.11 limit the number of slots to a maximum of 64. The solution was to
86 If you are having troubles, please use the {\bf auto} command in the {\bf
87 btape} program to test the functioning of your autochanger with Bacula. When
88 Bacula is running, please remember that for many distributions (e.g. FreeBSD,
89 Debian, ...) the Storage daemon runs as {\bf bacula.tape} rather than {\bf
90 root.root}, so you will need to ensure that the Storage daemon has sufficient
91 permissions to access the autochanger.
93 Some users have reported that the the Storage daemon blocks under certain
94 circumstances in trying to mount a volume on a drive that has a different
95 volume loaded. As best we can determine, this is simply a matter of
96 waiting a bit. The drive was previously in use writing a Volume, and
97 sometimes the drive will remain BLOCKED for a good deal of time (up to 7
98 minutes on a slow drive) waiting for the cassette to rewind and to unload
99 before the drive can be used with a different Volume.
102 \section{Knowing What SCSI Devices You Have}
103 \index[general]{Have!Knowing What SCSI Devices You }
104 \index[general]{Knowing What SCSI Devices You Have }
105 \index[general]{SCSI devices}
106 \index[general]{devices!SCSI}
116 to see what SCSI devices you have available. You can also:
120 cat /proc/scsi/sg/device_hdr /proc/scsi/sg/devices
124 to find out how to specify their control address ({\bf /dev/sg0} for the
125 first, {\bf /dev/sg1} for the second, ...) on the {\bf Changer Device = }
128 You can also use the excellent {\bf lsscsi} tool.
132 [1:0:2:0] tape SEAGATE ULTRIUM06242-XXX 1619 /dev/st0 /dev/sg9
133 [1:0:14:0] mediumx STK L180 0315 /dev/sch0 /dev/sg10
134 [2:0:3:0] tape HP Ultrium 3-SCSI G24S /dev/st1 /dev/sg11
135 [3:0:0:0] enclosu HP A6255A HP04 - /dev/sg3
136 [3:0:1:0] disk HP 36.4G ST336753FC HP00 /dev/sdd /dev/sg4
140 For more detailed information on what SCSI devices you have please see
141 the \borgxrlink{Linux SCSI Tricks}{SCSITricks}{problems}{section} of the \borgxrlink{Tape Testing}{TapeTestingChapter}{problems}{chapter} of the \problemsman{}.
143 Under FreeBSD, you can use:
151 To list the SCSI devices as well as the {\bf /dev/passn} that you will use on
152 the Bacula {\bf Changer Device = } directive.
154 Please check that your Storage daemon has permission to access this
157 The following tip for FreeBSD users comes from Danny Butroyd:
158 on reboot Bacula will NOT have permission to
159 control the device /dev/pass0 (assuming this is your changer device).
160 To get around this just edit the /etc/devfs.conf file and add the
161 following to the bottom:
164 own pass0 root:bacula
166 own nsa0.0 root:bacula
171 This gives the bacula group permission to write to the nsa0.0 device
172 too just to be on the safe side. To bring these changes into effect
175 /etc/rc.d/devfs restart
177 Basically this will stop you having to manually change permissions on these
178 devices to make Bacula work when operating the AutoChanger after a reboot.
181 \section{Example Scripts}
182 \index[general]{Scripts!Example }
183 \index[general]{Example Scripts }
185 Please read the sections below so that you understand how autochangers work
186 with Bacula. Although we supply a default {\bf mtx-changer} script, your
187 autochanger may require some additional changes. If you want to see examples
188 of configuration files and scripts, please look in the {\bf
189 \lt{}bacula-src\gt{}/examples/devices} directory where you will find an
190 example {\bf HP-autoloader.conf} Bacula Device resource, and several {\bf
191 mtx-changer} scripts that have been modified to work with different
197 \index[general]{Slots }
199 To properly address autochangers, Bacula must know which Volume is in each
200 {\bf slot} of the autochanger. Slots are where the changer cartridges reside
201 when not loaded into the drive. Bacula numbers these slots from one to the
202 number of cartridges contained in the autochanger.
204 Bacula will not automatically use a Volume in your autochanger unless it is
205 labeled and the slot number is stored in the catalog and the Volume is marked
206 as InChanger. This is because it must know where each volume is (slot) to
207 be able to load the volume.
208 For each Volume in your
209 changer, you will, using the Console program, assign a slot. This information
210 is kept in {\bf Bacula's} catalog database along with the other data for the
211 volume. If no slot is given, or the slot is set to zero, Bacula will not
212 attempt to use the autochanger even if all the necessary configuration records
213 are present. When doing a {\bf mount} command on an autochanger, you must
214 specify which slot you want mounted. If the drive is loaded with a tape
215 from another slot, it will unload it and load the correct tape, but
216 normally, no tape will be loaded because an {\bf unmount} command causes
217 Bacula to unload the tape in the drive.
220 You can check if the Slot number and InChanger flag are set by doing a:
225 in the Console program.
228 \section{Multiple Devices}
229 \index[general]{Devices!Multiple}
230 \index[general]{Multiple Devices}
232 Some autochangers have more than one read/write device (drive). The
233 new \ilink{Autochanger resource}{AutochangerRes} introduced in version
234 1.37 permits you to group Device resources, where each device
235 represents a drive. The Director may still reference the Devices (drives)
236 directly, but doing so, bypasses the proper functioning of the
237 drives together. Instead, the Director (in the Storage resource)
238 should reference the Autochanger resource name. Doing so permits
239 the Storage daemon to ensure that only one drive uses the mtx-changer
240 script at a time, and also that two drives don't reference the
243 Multi-drive requires the use of the {\bf
244 Drive Index} directive in the Device resource of the Storage daemon's
245 configuration file. Drive numbers or the Device Index are numbered beginning
246 at zero, which is the default. To use the second Drive in an autochanger, you
247 need to define a second Device resource and set the Drive Index to 1 for
248 that device. In general, the second device will have the same {\bf Changer
249 Device} (control channel) as the first drive, but a different {\bf Archive
252 As a default, Bacula jobs will prefer to write to a Volume that is
253 already mounted. If you have a multiple drive autochanger and you want
254 Bacula to write to more than one Volume in the same Pool at the same
255 time, you will need to set \ilink{Prefer Mounted Volumes} {PreferMountedVolumes}
256 in the Directors Job resource to {\bf no}. This will cause
257 the Storage daemon to maximize the use of drives.
260 \label{ConfigRecords}
261 \section{Device Configuration Records}
262 \index[general]{Records!Device Configuration }
263 \index[general]{Device Configuration Records }
265 Configuration of autochangers within Bacula is done in the Device resource of
266 the Storage daemon. Four records: {\bf Autochanger}, {\bf Changer Device},
267 {\bf Changer Command}, and {\bf Maximum Changer Wait} control how Bacula uses
270 These four records, permitted in {\bf Device} resources, are described in
271 detail below. Note, however, that the {\bf Changer Device} and the
272 {\bf Changer Command} directives are not needed in the Device resource
273 if they are present in the {\bf Autochanger} resource.
277 \item [Autochanger = {\it Yes|No} ]
278 \index[sd]{Autochanger }
279 The {\bf Autochanger} record specifies that the current device is or is not
280 an autochanger. The default is {\bf no}.
282 \item [Changer Device = \lt{}device-name\gt{}]
283 \index[sd]{Changer Device }
284 In addition to the Archive Device name, you must specify a {\bf Changer
285 Device} name. This is because most autochangers are controlled through a
286 different device than is used for reading and writing the cartridges. For
287 example, on Linux, one normally uses the generic SCSI interface for
288 controlling the autochanger, but the standard SCSI interface for reading and
289 writing the tapes. On Linux, for the {\bf Archive Device = /dev/nst0}, you
290 would typically have {\bf Changer Device = /dev/sg0}. Note, some of the more
291 advanced autochangers will locate the changer device on {\bf /dev/sg1}. Such
292 devices typically have several drives and a large number of tapes.
294 On FreeBSD systems, the changer device will typically be on {\bf /dev/pass0}
295 through {\bf /dev/passn}.
297 On Solaris, the changer device will typically be some file under {\bf
300 Please ensure that your Storage daemon has permission to access this
303 \item [Changer Command = \lt{}command\gt{}]
304 \index[sd]{Changer Command }
305 This record is used to specify the external program to call and what
306 arguments to pass to it. The command is assumed to be a standard program or
307 shell script that can be executed by the operating system. This command is
308 invoked each time that Bacula wishes to manipulate the autochanger. The
309 following substitutions are made in the {\bf command} before it is sent to
310 the operating system for execution:
315 %a = archive device name
316 %c = changer device name
317 %d = changer drive index base 0
320 %o = command (loaded, load, or unload)
327 An actual example for using {\bf mtx} with the {\bf mtx-changer} script (part
328 of the Bacula distribution) is:
332 Changer Command = "/etc/bacula/mtx-changer %c %o %S %a %d"
336 Where you will need to adapt the {\bf /etc/bacula} to be the actual path on
337 your system where the mtx-changer script resides. Details of the three
338 commands currently used by Bacula (loaded, load, unload) as well as the
339 output expected by Bacula are give in the {\bf Bacula Autochanger Interface}
342 \item [Maximum Changer Wait = \lt{}time\gt{}]
343 \index[sd]{Maximum Changer Wait }
344 This record is used to define the maximum amount of time that Bacula
345 will wait for an autoloader to respond to a command (e.g. load). The
346 default is set to 120 seconds. If you have a slow autoloader you may
347 want to set it longer.
349 If the autoloader program fails to respond in this time, it will be killed
350 and Bacula will request operator intervention.
352 \item [Drive Index = \lt{}number\gt{}]
353 \index[sd]{Drive Index }
354 This record allows you to tell Bacula to use the second or subsequent
355 drive in an autochanger with multiple drives. Since the drives are
356 numbered from zero, the second drive is defined by
365 To use the second drive, you need a second Device resource definition in the
366 Bacula configuration file. See the Multiple Drive section above in this
367 chapter for more information.
370 In addition, for proper functioning of the Autochanger, you must
371 define an Autochanger resource.
372 \input{autochangerres}
375 \section{An Example Configuration File}
376 \index[general]{Example Configuration File }
377 \index[general]{File!Example Configuration }
379 The following two resources implement an autochanger:
386 Changer Device = /dev/sg0
387 Changer Command = "/etc/bacula/mtx-changer %c %o %S %a %d"
393 Archive Device = /dev/nst0 # Normal archive device
396 AutomaticMount = yes;
402 where you will adapt the {\bf Archive Device}, the {\bf Changer Device}, and
403 the path to the {\bf Changer Command} to correspond to the values used on your
406 \section{A Multi-drive Example Configuration File}
407 \index[general]{Multi-drive Example Configuration File }
409 The following resources implement a multi-drive autochanger:
415 Device = Drive-1, Drive-2
416 Changer Device = /dev/sg0
417 Changer Command = "/etc/bacula/mtx-changer %c %o %S %a %d"
424 Archive Device = /dev/nst0 # Normal archive device
427 AutomaticMount = yes;
435 Archive Device = /dev/nst1 # Normal archive device
438 AutomaticMount = yes;
445 where you will adapt the {\bf Archive Device}, the {\bf Changer Device}, and
446 the path to the {\bf Changer Command} to correspond to the values used on your
449 \label{SpecifyingSlots}
450 \section{Specifying Slots When Labeling}
451 \index[general]{Specifying Slots When Labeling }
452 \index[general]{Labeling!Specifying Slots When }
454 If you add an {\bf Autochanger = yes} record to the Storage resource in your
455 Director's configuration file, the Bacula Console will automatically prompt
456 you for the slot number when the Volume is in the changer when
457 you {\bf add} or {\bf label} tapes for that Storage device. If your
458 {\bf mtx-changer} script is properly installed, Bacula will automatically
459 load the correct tape during the label command.
462 {\bf Autochanger = yes} in the Storage daemon's Device resource
463 as we have described above in
464 order for the autochanger to be used. Please see the
465 \ilink{Storage Resource}{Autochanger1} in the Director's chapter
467 \ilink{Device Resource}{Autochanger} in the Storage daemon
468 chapter for more details on these records.
470 Thus all stages of dealing with tapes can be totally automated. It is also
471 possible to set or change the Slot using the {\bf update} command in the
472 Console and selecting {\bf Volume Parameters} to update.
474 Even though all the above configuration statements are specified and correct,
475 Bacula will attempt to access the autochanger only if a {\bf slot} is non-zero
476 in the catalog Volume record (with the Volume name).
478 If your autochanger has barcode labels, you can label all the Volumes in
479 your autochanger one after another by using the {\bf label barcodes} command.
480 For each tape in the changer containing a barcode, Bacula will mount the tape
481 and then label it with the same name as the barcode. An appropriate Media
482 record will also be created in the catalog. Any barcode that begins with the
483 same characters as specified on the "CleaningPrefix=xxx" command, will be
484 treated as a cleaning tape, and will not be labeled. For example with:
490 Cleaning Prefix = "CLN"
495 Any slot containing a barcode of CLNxxxx will be treated as a cleaning tape
496 and will not be mounted.
498 Please note that Volumes must be pre-labeled to be automatically used in
499 the autochanger during a backup. If you do not have a barcode reader, this
500 is done manually (or via a script).
503 \section{Changing Cartridges}
504 \index[general]{Changing Cartridges }
505 If you wish to insert or remove cartridges in your autochanger or
506 you manually run the {\bf mtx} program, you must first tell Bacula
507 to release the autochanger by doing:
512 (change cartridges and/or run mtx)
517 If you do not do the unmount before making such a change, Bacula
518 will become completely confused about what is in the autochanger
519 and may stop function because it expects to have exclusive use
520 of the autochanger while it has the drive mounted.
524 \section{Dealing with Multiple Magazines}
525 \index[general]{Dealing with Multiple Magazines }
526 \index[general]{Magazines!Dealing with Multiple }
528 If you have several magazines or if you insert or remove cartridges from a
529 magazine, you should notify Bacula of this. By doing so, Bacula will as
530 a preference, use Volumes that it knows to be in the autochanger before
531 accessing Volumes that are not in the autochanger. This prevents unneeded
532 operator intervention.
534 If your autochanger has barcodes (machine readable tape labels), the task of
535 informing Bacula is simple. Every time, you change a magazine, or add or
536 remove a cartridge from the magazine, simply do
542 (insert new magazine)
548 in the Console program. This will cause Bacula to request the autochanger to
549 return the current Volume names in the magazine. This will be done without
550 actually accessing or reading the Volumes because the barcode reader does this
551 during inventory when the autochanger is first turned on. Bacula will ensure
552 that any Volumes that are currently marked as being in the magazine are marked
553 as no longer in the magazine, and the new list of Volumes will be marked as
554 being in the magazine. In addition, the Slot numbers of the Volumes will be
555 corrected in Bacula's catalog if they are incorrect (added or moved).
557 If you do not have a barcode reader on your autochanger, you have several
561 \item You can manually set the Slot and InChanger flag using the {\bf update
562 volume} command in the Console (quite painful).
564 \item You can issue a
572 command that will cause Bacula to read the label on each of the cartridges in
573 the magazine in turn and update the information (Slot, InChanger flag) in the
574 catalog. This is quite effective but does take time to load each cartridge
575 into the drive in turn and read the Volume label.
577 \item You can modify the mtx-changer script so that it simulates an
578 autochanger with barcodes. See below for more details.
582 \section{Simulating Barcodes in your Autochanger}
583 \index[general]{Autochanger!Simulating Barcodes in your }
584 \index[general]{Simulating Barcodes in your Autochanger }
586 You can simulate barcodes in your autochanger by making the {\bf mtx-changer}
587 script return the same information that an autochanger with barcodes would do.
588 This is done by commenting out the one and only line in the {\bf list)} case,
593 ${MTX} -f $ctl status | grep " *Storage Element [0-9]*:.*Full" | awk "{print \$3 \$4}" | sed "s/Full *\(:VolumeTag=\)*//"
597 at approximately line 99 by putting a \# in column one of that line, or by
598 simply deleting it. Then in its place add a new line that prints the contents
599 of a file. For example:
603 cat /etc/bacula/changer.volumes
607 Be sure to include a full path to the file, which can have any name. The
608 contents of the file must be of the following format:
619 Where the 1, 2, 3 are the slot numbers and Volume1, Volume2, ... are the
620 Volume names in those slots. You can have multiple files that represent the
621 Volumes in different magazines, and when you change magazines, simply copy the
622 contents of the correct file into your {\bf /etc/bacula/changer.volumes} file.
623 There is no need to stop and start Bacula when you change magazines, simply
624 put the correct data in the file, then run the {\bf update slots} command, and
625 your autochanger will appear to Bacula to be an autochanger with barcodes.
628 \section{The Full Form of the Update Slots Command}
629 \index[general]{Full Form of the Update Slots Command }
630 \index[general]{Command!Full Form of the Update Slots }
632 If you change only one cartridge in the magazine, you may not want to scan all
633 Volumes, so the {\bf update slots} command (as well as the {\bf update slots
634 scan} command) has the additional form:
638 update slots=n1,n2,n3-n4, ...
642 where the keyword {\bf scan} can be appended or not. The n1,n2, ... represent
643 Slot numbers to be updated and the form n3-n4 represents a range of Slot
644 numbers to be updated (e.g. 4-7 will update Slots 4,5,6, and 7).
646 This form is particularly useful if you want to do a scan (time expensive) and
647 restrict the update to one or two slots.
649 For example, the command:
653 update slots=1,6 scan
657 will cause Bacula to load the Volume in Slot 1, read its Volume label and
658 update the Catalog. It will do the same for the Volume in Slot 6. The command:
667 will read the barcoded Volume names for slots 1,2,3 and 6 and make the
668 appropriate updates in the Catalog. If you don't have a barcode reader or have
669 not modified the mtx-changer script as described above, the above command will
670 not find any Volume names so will do nothing.
673 \section{FreeBSD Issues}
674 \index[general]{Issues!FreeBSD }
675 \index[general]{FreeBSD Issues }
677 If you are having problems on FreeBSD when Bacula tries to select a tape, and
678 the message is {\bf Device not configured}, this is because FreeBSD has made
679 the tape device {\bf /dev/nsa1} disappear when there is no tape mounted in the
680 autochanger slot. As a consequence, Bacula is unable to open the device. The
681 solution to the problem is to make sure that some tape is loaded into the tape
682 drive before starting Bacula. This problem is corrected in Bacula versions
686 \borgxrlink{Tape Testing}{FreeBSDTapes}{problems}{chapter} of the \problemsman{} for {\bf important} information concerning your tape drive before doing the
688 \label{AutochangerTesting}
690 \section{Testing Autochanger and Adapting mtx-changer script}
691 \index[general]{Testing the Autochanger }
692 \index[general]{Adapting Your mtx-changer script}
695 Before attempting to use the autochanger with Bacula, it is preferable to
696 "hand-test" that the changer works. To do so, we suggest you do the
697 following commands (assuming that the {\bf mtx-changer} script is installed in
698 {\bf /etc/bacula/mtx-changer}):
702 \item [Make sure Bacula is not running.]
704 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ list \ 0 \ /dev/nst0 \ 0]
705 \index[sd]{mtx-changer list}
707 This command should print:
719 or one number per line for each slot that is occupied in your changer, and
720 the number should be terminated by a colon ({\bf :}). If your changer has
721 barcodes, the barcode will follow the colon. If an error message is printed,
722 you must resolve the problem (e.g. try a different SCSI control device name
723 if {\bf /dev/sg0} is incorrect). For example, on FreeBSD systems, the
724 autochanger SCSI control device is generally {\bf /dev/pass2}.
726 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ listall \ 0 \ /dev/nst0 \ 0]
727 \index[sd]{mtx-changer listall}
729 This command should print:
733 Drive content: D:Drive num:F:Slot loaded:Volume Name
734 D:0:F:2:vol2 or D:Drive num:E
739 S:1:F:vol1 S:Slot num:F:Volume Name
740 S:2:E or S:Slot num:E
743 Import/Export tray slots:
744 I:10:F:vol10 I:Slot num:F:Volume Name
745 I:11:E or I:Slot num:E
751 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ transfer \ 1 \ 2]
752 \index[sd]{mtx-changer listall}
754 This command should transfer a volume from source (1) to destination (2)
756 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ slots ]
757 \index[sd]{mtx-changer slots}
759 This command should return the number of slots in your autochanger.
761 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ unload \ 1 \ /dev/nst0 \ 0 ]
762 \index[sd]{mtx-changer unload}
764 If a tape is loaded from slot 1, this should cause it to be unloaded.
766 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ load \ 3 \ /dev/nst0 \ 0 ]
767 \index[sd]{mtx-changer load}
769 Assuming you have a tape in slot 3, it will be loaded into drive (0).
772 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ loaded \ 0 \ /dev/nst0 \ 0]
773 \index[sd]{mtx-changer loaded}
776 Note, we have used an "illegal" slot number 0. In this case, it is simply
777 ignored because the slot number is not used. However, it must be specified
778 because the drive parameter at the end of the command is needed to select
781 \item [/etc/bacula/mtx-changer \ /dev/sg0 \ unload \ 3 /dev/nst0 \ 0]
783 will unload the tape into slot 3.
787 Once all the above commands work correctly, assuming that you have the right
788 {\bf Changer Command} in your configuration, Bacula should be able to operate
789 the changer. The only remaining area of problems will be if your autoloader
790 needs some time to get the tape loaded after issuing the command. After the
791 {\bf mtx-changer} script returns, Bacula will immediately rewind and read the
792 tape. If Bacula gets rewind I/O errors after a tape change, you will probably
793 need to insert a {\bf sleep 20} after the {\bf mtx} command, but be careful to
794 exit the script with a zero status by adding {\bf exit 0} after any additional
795 commands you add to the script. This is because Bacula checks the return
796 status of the script, which should be zero if all went well.
798 You can test whether or not you need a {\bf sleep} by putting the following
799 commands into a file and running it as a script:
804 /etc/bacula/mtx-changer /dev/sg0 unload 1 /dev/nst0 0
805 /etc/bacula/mtx-changer /dev/sg0 load 3 /dev/nst0 0
806 mt -f /dev/st0 rewind
811 If the above script runs, you probably have no timing problems. If it does not
812 run, start by putting a {\bf sleep 30} or possibly a {\bf sleep 60} in the
813 script just after the mtx-changer load command. If that works, then you should
814 move the sleep into the actual {\bf mtx-changer} script so that it will be
815 effective when Bacula runs.
817 A second problem that comes up with a small number of autochangers is that
818 they need to have the cartridge ejected before it can be removed. If this is
819 the case, the {\bf load 3} will never succeed regardless of how long you wait.
820 If this seems to be your problem, you can insert an eject just after the
821 unload so that the script looks like:
826 /etc/bacula/mtx-changer /dev/sg0 unload 1 /dev/nst0 0
827 mt -f /dev/st0 offline
828 /etc/bacula/mtx-changer /dev/sg0 load 3 /dev/nst0 0
829 mt -f /dev/st0 rewind
834 Obviously, if you need the {\bf offline} command, you should move it into the
835 mtx-changer script ensuring that you save the status of the {\bf mtx} command
836 or always force an {\bf exit 0} from the script, because Bacula checks the
837 return status of the script.
839 As noted earlier, there are several scripts in {\bf
840 \lt{}bacula-source\gt{}/examples/devices} that implement the above features,
841 so they may be a help to you in getting your script to work.
843 If Bacula complains "Rewind error on /dev/nst0. ERR=Input/output error." you
844 most likely need more sleep time in your {\bf mtx-changer} before returning to
845 Bacula after a load command has been completed.
849 \section{Using the Autochanger}
850 \index[general]{Using the Autochanger }
851 \index[general]{Autochanger!Using the }
853 Let's assume that you have properly defined the necessary Storage daemon
854 Device records, and you have added the {\bf Autochanger = yes} record to the
855 Storage resource in your Director's configuration file.
857 Now you fill your autochanger with say six blank tapes.
859 What do you do to make Bacula access those tapes?
861 One strategy is to prelabel each of the tapes. Do so by starting Bacula, then
862 with the Console program, enter the {\bf label} command:
867 Connecting to Director rufus:8101
868 1000 OK: rufus-dir Version: 1.26 (4 October 2002)
873 it will then print something like:
877 Using default Catalog name=BackupDB DB=bacula
878 The defined Storage resources are:
881 Select Storage resource (1-2): 1
885 I select the autochanger (1), and it prints:
889 Enter new Volume name: TestVolume1
890 Enter slot (0 for none): 1
894 where I entered {\bf TestVolume1} for the tape name, and slot {\bf 1} for the
902 Select the Pool (1-2): 1
906 I select the Default pool. This will be automatically done if you only have a
907 single pool, then Bacula will proceed to unload any loaded volume, load the
908 volume in slot 1 and label it. In this example, nothing was in the drive, so
913 Connecting to Storage daemon Autochanger at localhost:9103 ...
914 Sending label command ...
915 3903 Issuing autochanger "load slot 1" command.
916 3000 OK label. Volume=TestVolume1 Device=/dev/nst0
917 Media record for Volume=TestVolume1 successfully created.
918 Requesting mount Autochanger ...
919 3001 Device /dev/nst0 is mounted with Volume TestVolume1
925 You may then proceed to label the other volumes. The messages will change
926 slightly because Bacula will unload the volume (just labeled TestVolume1)
927 before loading the next volume to be labeled.
929 Once all your Volumes are labeled, Bacula will automatically load them as they
932 To "see" how you have labeled your Volumes, simply enter the {\bf list
933 volumes} command from the Console program, which should print something like
939 Using default Catalog name=BackupDB DB=bacula
943 Select the Pool (1-2): 1
944 +-------+----------+--------+---------+-------+--------+----------+-------+------+
945 | MedId | VolName | MedTyp | VolStat | Bites | LstWrt | VolReten | Recyc | Slot |
946 +-------+----------+--------+---------+-------+--------+----------+-------+------+
947 | 1 | TestVol1 | DDS-4 | Append | 0 | 0 | 30672000 | 0 | 1 |
948 | 2 | TestVol2 | DDS-4 | Append | 0 | 0 | 30672000 | 0 | 2 |
949 | 3 | TestVol3 | DDS-4 | Append | 0 | 0 | 30672000 | 0 | 3 |
951 +-------+----------+--------+---------+-------+--------+----------+-------+------+
957 \section{Barcode Support}
958 \index[general]{Support!Barcode }
959 \index[general]{Barcode Support }
961 Bacula provides barcode support with two Console commands, {\bf label
962 barcodes} and {\bf update slots}.
964 The {\bf label barcodes} will cause Bacula to read the barcodes of all the
965 cassettes that are currently installed in the magazine (cassette holder) using
966 the {\bf mtx-changer} {\bf list} command. Each cassette is mounted in turn and
967 labeled with the same Volume name as the barcode.
969 The {\bf update slots} command will first obtain the list of cassettes and
970 their barcodes from {\bf mtx-changer}. Then it will find each volume in turn
971 in the catalog database corresponding to the barcodes and set its Slot to
972 correspond to the value just read. If the Volume is not in the catalog, then
973 nothing will be done. This command is useful for synchronizing Bacula with the
974 current magazine in case you have changed magazines or in case you have moved
975 cassettes from one slot to another. If the autochanger is empty, nothing will
978 The {\bf Cleaning Prefix} statement can be used in the Pool resource to define
979 a Volume name prefix, which if it matches that of the Volume (barcode) will
980 cause that Volume to be marked with a VolStatus of {\bf Cleaning}. This will
981 prevent Bacula from attempting to write on the Volume.
983 \section{Use bconsole to display Autochanger content}
985 The {\bf status slots storage=xxx} command displays autochanger content.
989 Slot | Volume Name | Status | Type | Pool | Loaded |
990 ------+-----------------+----------+-------------------+----------------+---------|
991 1 | 00001 | Append | DiskChangerMedia | Default | 0 |
992 2 | 00002 | Append | DiskChangerMedia | Default | 0 |
993 3*| 00003 | Append | DiskChangerMedia | Scratch | 0 |
998 If you see a {\bf *} near the slot number, you have to run {\bf update slots}
999 command to synchronize autochanger content with your catalog.
1003 \section{Bacula Autochanger Interface}
1004 \index[general]{Interface!Bacula Autochanger }
1005 \index[general]{Bacula Autochanger Interface }
1007 Bacula calls the autochanger script that you specify on the {\bf Changer
1008 Command} statement. Normally this script will be the {\bf mtx-changer} script
1009 that we provide, but it can in fact be any program. The only requirement
1010 for the script is that it must understand the commands that
1011 Bacula uses, which are {\bf loaded}, {\bf load}, {\bf
1012 unload}, {\bf list}, and {\bf slots}. In addition,
1013 each of those commands must return the information in the precise format as
1018 - Currently the changer commands used are:
1019 loaded -- returns number of the slot that is loaded, base 1,
1020 in the drive or 0 if the drive is empty.
1021 load -- loads a specified slot (note, some autochangers
1022 require a 30 second pause after this command) into
1024 unload -- unloads the device (returns cassette to its slot).
1025 list -- returns one line for each cassette in the autochanger
1026 in the format <slot>:<barcode>. Where
1027 the {\bf slot} is the non-zero integer representing
1028 the slot number, and {\bf barcode} is the barcode
1029 associated with the cassette if it exists and if you
1030 autoloader supports barcodes. Otherwise the barcode
1032 slots -- returns total number of slots in the autochanger.
1036 Bacula checks the exit status of the program called, and if it is zero, the
1037 data is accepted. If the exit status is non-zero, Bacula will print an
1038 error message and request the tape be manually mounted on the drive.