X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=docs%2Ftapechangers.txt;h=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391;hb=d92f70685083588e2a7ce6bc312a735f6937b5a6;hp=b4fb9b179102c1f510fbffbdc5311241ecaff63f;hpb=c9bb64dd8260123d77b6f7be0f051f450b193e66;p=debian%2Famanda

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-
-     Chapter 8. AMANDA Tape Changer Support
-Prev  Part II. About Tapes and Changers  Next
-
--------------------------------------------------------------------------------
-
-Chapter 8. AMANDA Tape Changer Support
-
-
-James da Silva
-
-Original text
-AMANDA Core Team
-<jds@amanda.org>
-
-Stefan G. Weichinger
-
-XML-conversion;Updates
-AMANDA Core Team
-<sgw@amanda.org>
-Table of Contents
-
-
-  Introduction
-
-  Specifying_a_tape_changer_in_amanda.conf
-
-  Device-specific_tapechanger_script
-
-  Slot_names_and_the_"current"_slot
-
-  Operator_interface
-
-  How_amdump_interacts_with_the_tape_changer
-
-  Builtin_tape-changers
-
-
-        chg-multi_(formerly_chg-generic)
-
-        chg-manual_(formerly_no-changer)
-
-        chg-mtx_(formerly_hp-changer)
-
-        chg-zd-mtx
-
-        chg-scsi-chio_(formerly_seagate-changer,_then_chg-chio)
-
-        chg-scsi_(new_interface,_try_to_drive_a_robot_with_direct_scsi
-        commands)
-
-        chg-chio
-
-        chg-chs
-
-        chg-rth
-
-        chg-juke
-
-        chg-rait
-
-        chg-disk
-
-        chg-iomega
-
-        chg-null
-
-
-
-Note
-
-Refer to http://www.amanda.org/docs/tapechangers.html for the current version
-of this document.
-
- Introduction
-
-This document outlines the tape changer support design of AMANDA 2.2 and
-beyond. It defines a small interface for changer software to follow so that
-AMANDA can remain device-independent but still support the widest range of tape
-software and hardware possible.
-The interface is a bit simplistic and has only had complications added when
-there is a body of field experience.
-
- Specifying a tape changer in amanda.conf
-
-All device-specifics are hidden by a glue program that the rest of AMANDA calls
-to interact with the tape changer.
-The name of this changer program is given by the "tpchanger" variable in the
-file amanda.conf. Example entry:
-
-  tpchanger "chg-multi"	   # use multi-unit tape changer emulator
-  	
-
-The tapedev parameter is ignored if a tpchanger program is specified, unless
-the changer program itself reads tapedev from amanda.conf. The chg-multi
-changer doesn't, as it reads all its configuration arguments from its own
-configuration file, specified as changerfile.
-If the tpchanger program does not begin with a '/', AMANDA expects it to reside
-in libexecdir, and possibly have the version suffix appended depending on how
-AMANDA was configured.
-Two other amanda.conf parameters are available for changer use, however their
-definition is left entirely up to the changer script itself. They are
-changerfile and changerdev. Typically changerfile will point to the
-configuration file specific to the changer, or be a base name of several
-related changer files. The changerdev variable may point to the /dev entry used
-to access the changer device.
-See the documentation with the specific changer you're interested in to see
-exaclty how these variables are used (if at all).
-
- Device-specific tapechanger script
-
-The tape changer script/program is always from the directory with amanda.conf.
-It is never passed the configuration name it is running on behalf of, but since
-amgetconf works without a name from the current directory, that should be
-sufficient.
-The script/program must support the following commands:
-
-* <tpchanger> -slot <slot-specifier>
-
-If changer is loaded, unloads the current slot (if different than "slot-
-specifier") and puts that tape away, then loads the requested slot. See the
-next section for the list of valid slot requests.
-Outputs to stdout the slot name and name of the device file to access the tape
-on success, or a slot name and error text.
-Returns 0 on success.
-Returns 1 on positioning error (eg at bottom of gravity stacker or slot empty).
-Returns 2 any other fatal error. The slot name may be invalid, but must be
-present. Error message goes to stdout in place of device name.
-Examples:
-
-  		% chg-multi -slot 0
-  		0 /dev/nrst8			# exitcode returned is 0
-
-  		% chg-multi -slot 1
-  		1 slot 1 is empty		# exitcode returned is 1
-
-  		% chg-multi -slot bogus-slot
-  		<none> no slot `bogus-slot'	# exitcode returned is 2
-
-
-* <tpchanger> -info
-
-Outputs to stdout three or more fields:
-The current slot string (required)
-The number of slots (required)
-Flag indicating whether the changer can go backwards
-(0 if it can't, 1 if it can). (required)
-Flag indicating whether the changer is searchable
-(optional). Shows whether the changer supports the -search and -label commands
-and is able to load a tape given only the AMANDA label string (0 or omitted if
-it can't, 1 if it can). (optional)
-Examples:
-
-  		% chg-multi -info
-  		0 10 1				# exitcode returned is 0
-
-  		% chg-zd-mtx -info
-  		0 10 1 1
-
-
-* <tpchanger> -reset
-
-Resets the changer to known state and loads the first slot.
-Output and error handling are the same as
-"<tpchanger> -slot first"
-In the case of a gravity stacker that must be reset by hand, this could be run
-(via " amtape <conf> reset") to inform the software the stacker is positioned
-back at the top.
-Examples:
-
-  		% chg-multi -reset
-  		0 /dev/nrst8			# exitcode returned is 0
-
-  		% chg-multi -reset
-  		0 slot 0 is empty		# exitcode returned is 1
-
-  		% chg-multi -reset
-  		0 tape-changer not responding	# exitcode returned is 2
-
-
-* <tpchanger> -eject
-
-Unloads the current slot (if loaded) and puts that tape away.
-Output and error handling are the same as the -slot command.
-Note that a tape may or may not be loaded when this command completes,
-depending on the hardware.
-Examples:
-
-  		% chg-multi -eject
-  		0 /dev/nrst8			# exitcode returned is 0
-
-  		% chg-multi -eject
-  		0 drive was not loaded		# exitcode returned is 1
-
-The tape changer program MAY support the following commands:
-
-* <tpchanger> -search <labelstr>
-
-Loads an AMANDA tape by name (labelstr).
-Output and error handling are the same as the -slot command.
-taper, amcheck and amtape will use this command if the changer reports it is
-searchable.
-Example:
-
-  		% chg-zd-mtx -search DailySet005
-  		5 /dev/nrst8			# exitcode returned is 0
-
--<tpchanger> -label <labelstr> Associates the AMANDA label <labelstr> with the
-barcode of the currently loaded (in the tape drive) tape.
-Outputs to stdout the current slot and tape device. amlabel will use this
-command if your changer is searchable to build up the barcode database.
-Example:
-
-  		% chg-zd-mtx -label DailySet006
-  		6 /dev/nrst8			# exitcode returned is 0
-
-For all the commands:
-An exit code of 0 implies that the operation was completely successful, and the
-output may be parsed by the AMANDA code as described above.
-For non-zero exit codes, the first field is still the slot name, but the actual
-error messages are not fixed. They are just displayed and/or logged as-is by
-the calling AMANDA program.
-An exit code of 1 implies the operation failed in a benign way, for example an
-empty slot or an attempt to go backwards in a gravity stacker. The calling
-AMANDA program will print the error message if appropriate and continue,
-perhaps requesting a different slot be loaded.
-Any other exit code is considered fatal and will cause AMANDA to stop
-attempting to talk to the tape changer.
-
- Slot names and the "current" slot
-
-Some tape changers, such as carousels and gravity stackers, have a hardware
-notion of current position. Others have no current position when no tape is
-loaded: all tapes are in their slots and the changer arm is docked away from
-the slots.
-Nevertheless, AMANDA requires tape-changer scripts to maintain the notion of a
-"current" position. This is for performance reasons: as tapes tend to be loaded
-into the rack in order, and AMANDA uses them in order, the next tape to use can
-be found much quicker if the position of the current one is remembered. As an
-example, the chg-multi script maintains the current position in a chg-
-multi.state file (or any other file specified in a `statefile' line in the
-changer configuration file).
-AMANDA does not care how slots are available or how they are named. They could
-be numbered 0 to N-1, numbered 1 to N, or even designated by letter, A .. Z.
-The only requirement is that the names do not contain whitespace and that the
-names "current", "next", "prev", "first", "last" and "advance" retain their
-meaning as follows:
-current The position of the last loaded tape, as described above
-next The position after current, wrapping from the last slot to the first.
-prev The position before current, wrapping from the first slot to the last.
-first The first slot in the tape rack.
-last The last slot in the tape rack.
-advance The same as "next" except the next tape may not be loaded if the
-changer supports advancing to the next slot without putting that tape in the
-drive.
-The current position must be updated even if there is a positioning error (such
-as "empty slot"). This allows amanda to step through the entire tape rack by
-issuing successive "slot next" positioning commands.
-
- Operator interface
-
-The amtape program is the main operator interface to AMANDA's tape changer
-support. The commands supported include:
-amtape <conf> slot <slot-specifier> Load the tape from the specified slot into
-the drive
-amtape <conf> eject Send an eject command to the tape-changer. Effect is
-changer specific.
-amtape <conf> reset Send a reset command to the tape-changer. Effect is changer
-specific.
-amtape <conf> show Go through the entire tape rack, showing the labels of all
-amanda tapes encountered.
-amtape <conf> label <label> Find and load the tape with the specified label
-amtape <conf> taper Perform taper's scan algorithm (see below), loading the
-tape which would be picked for the next amdump run.
-amtape <conf> clean If a cleaning tape is defined by the changer, load it in
-the drive and put it away when done.
-amtape <conf> device Output the current tape device name.
-amtape <conf> current Display the contents of the current slot.
-amtape <conf> update Scan the entire tape rack and update the barcode database.
-See the amtape(8) man page for more details.
-In addition to amtape, amlabel has been modified to allow optionally specifying
-a slot:
-amlabel <conf> <label> [slot <slot-specifier>]
-amcheck looks for the next tape in the rack the same way the taper does. If
-multiple tapes are used in one night, amcheck attempts to find all the needed
-tapes in turn if the tape-changer is random access. On a one-way gravity
-stacker, amcheck only finds the first tape, since finding the subsequent ones
-would put the first one out of reach of that night's amdump run.
-amrestore and amrecover do not yet include any tape changer support directly,
-as amrestore knows nothing about the amanda.conf files or server-side
-databases. This is a deliberate decision to keep amrestore independent, so it
-can be run from any host with a tape drive, even if the original tape server
-host is down. To use amrestore in a tape-changer environment, use amtape to
-find the right tape, then run amrestore giving the resulting tape device name.
-
- How amdump interacts with the tape changer
-
-AMANDA does not require a particular tape label for a run. Any label that
-matches the labelstr regex and is determined to be "inactive" according to the
-tapelist database, may be written to. However, there is a preferred 'next'
-tape, the one that is next in the cycle implied by the current tapelist.
-amdump uses two algorithms, depending on whether the tape changer can go
-backwards in the rack or not. If multiple tapes are needed in a single run,
-this algorithm is repeated in turn whenever a new tape is required.
-Normal tape changers (those that can go backwards):
-With a full-access tape changer, amdump searches the entire rack for the
-preferred tape label. This tape will usually be found at the current or next
-position, but might be located anywhere. If the tape is found, it is used. If
-it is not found, the first tape encountered that matches the labelstr and is
-not active is picked.
-Gravity stackers (anything that can not go backwards):
-To avoid going all the way to the bottom of the stacker only to find that the
-preferred tape isn't present and nothing can be done, AMANDA picks the first
-tape (starting at the current position) that matches the labelstr and is not
-active, regardless of whether it is the preferred tape.
-
- Builtin tape-changers
-
-
- chg-multi (formerly chg-generic)
-
-This tape changer script supports several common configurations:
-
-* Using multiple tape drives in a single host to emulate a tape changer. This
-  can also be used with a single physical drive to write several tapes in an
-  AMANDA run.
-
-
-* Using a gravity stacker or a real changer configured to sequentially load the
-  next tape when the current one is ejected. Also supports a changer which
-  cycles to the first tape after loading the last one.
-
-
-* Using a changer accessed through several "virtual" tape devices which
-  determine which slot actually gets loaded in the tape drive.
-
-The advantage of this changer script is that you do not need to get into the
-complexity of dealing with a real changer interface. All the action goes
-through the tape device interface with standard mt commands, which eases many
-portability issues. Many common tape jukeboxes can be configured in a
-sequential or cycle mode.
-chg-multi ignores `tapedev' and `changerdev' because `changerfile' may specify
-several tape devices to be used. A sample configuration file may be found in
-example/chg-multi.conf.
-
- chg-manual (formerly no-changer)
-
-This is a poor man's tape changer that requires the backup operator to change
-tapes manually. It expects `tapedev' in amanda.conf to point to a valid tape
-device, and stores some status data in files whose names start with the
-`changerfile'. `changerdev' is ignored.
-
- chg-mtx (formerly hp-changer)
-
-An mtx-based tape changer script. `changerdev' must specify the tape device
-controlled by the mtx program, and `tapedev' must point to the no-rewind tape
-device to be used. More than likely, both `changerdev' and `tapedev' will
-reference the same device file. `changerfile' must specify a prefix for status
-files maintained by this script. It will maintain files named `changerfile'/
-changer-clean and `changerfile'/changer-access. You may have to edit the script
-to specify which slot contains a cleaning tape (cleanslot).
-The mtx program must support commands such as `-s', `-l' and `-u'. If the one
-you've got requires `status', `load' and `unload', you should use chg-zd-mtx
-instead (see below).
-
- chg-zd-mtx
-
-Based on chg-mtx, but modified in order to support the Zubkoff/Dandelion
-version of mtx. Eric DOUTRELEAU <Eric.Doutreleau@int-evry.fr>, who contributed
-this script, reported that it works on a Solaris/sparc box with a HP 1557A
-stacker.
-In addition to the `changerfile'-clean and the `changerfile'-access files, it
-maintains a `changerfile'-slot file that indicates the currently loaded slot.
-There are lots of comments at the start of the script describing how to set it
-up.
-
- chg-scsi-chio (formerly seagate-changer, then chg-chio)
-
-A C program that relies on scsi tape-changer interfaces. It may either use the
-tape changer interface specified in chio.h (Gerd Knor's SCSI media changer
-driver, a Linux kernel loadable module), or it may use built-in tape changer
-interfaces available on HPUX, Solaris 2.5, IRIX and possibly others, but only
-the chio and HPUX interfaces are currently implemented . `tapedev' specifies
-the tape device to be used; `changer_dev' is the device used to talk to the
-kernel module (for chio, usually /dev/ch0), and `changerfile' specifies a
-filename in which the current slot number will be stored.
-Now there is another way, to get the chg-scsi a little bit more flexible. If
-you use only one digit in the `tapedev' parameter, the chg-scsi expects that
-changerfile points to a real configuration file, not only a counting file. In
-this configuration file you may specify that the tapedrive needs an eject
-command and an optional waittime, necessary after inserting the tape into the
-drive. You are also able to configure a range of slots which should be used by
-your configuration. The idea behind this is, that you don't want AMANDA to
-cycle all the tapes if AMANDA searches exactly one tape. If you have a library
-which supports more than one drive you can also specify which drive to use. For
-each configuration (there should be at least one) you have to specify a file,
-where AMANDA remembers which tape is actually in the drive. For future use
-there is also some stuff for cleaning the drives.
-In amanda.conf:
-
-  tapedev "x"       with x between 0 and 9, selects the configuration to use
-  changerfile "filename"            specifies the changer configuration file
-  	
-
-In the changer-config-file the following could be set:
-
-  number_configs x
-  #	x between 0 and 9 	number of configurations defined. This should be the
-  first parameter in the config-file.
-  eject	x
-  #	x 0 or 1		1 means that the drives need an eject command, before the robot
-  can handle the tape.
-  sleep	x
-  #	x between 0 and MAX_INT specifies the seconds to wait before the drive
-  could be used after inserting a tape. 5 should be OK.
-  cleanmax x	
-  #	x some positive int	How many cleanings does a cleaning tape survive
-  changerdev  <device>
-  #				The device for the robot
-  	
-
-And then there come some configuration sections, separated by the word `config`
-followed by the ordinal of that configuration (0 to 9). In each configuration
-section you should specify:
-
-  drivenum x		x between 0 and the number of drives in the library
-  This one specifies the drive to
-  use with this configuration
-  dev	<device>				The device for the tapedrive
-  startuse    x		x between 0 and maximum slotnumber of your library
-  Starting here we may use the tapes
-  enduse	 x		x between start and maximum slotnumber
-  This is the last tape we may use
-  in this configuration. If we reach
-  this one the next will be start..
-  statfile <filename>				Here we remember the last used
-  slot for this configuration
-  cleancart	x	x between 0 and maximum slotnumber
-  In this slot we find the
-  cleaning tape
-  cleanfile <filename>				Here we will remember how
-  often we used the cleaning tape
-  usagecount <filename>				This points to a file which is
-  deleted after cleaning the drive
-  e.g. the usagetime of the drive
-  	
-
-Comments begin with an '#' until end of line. Allowed separators are TAB and
-SPACE.
-
- chg-scsi (new interface, try to drive a robot with direct scsi commands)
-
-The config and the syntax is the same as for chg-scsi-chio. New is the config
-type
-emubarcode 1
-With this option and the option labelfile chg-scsi will try to create an
-inventory. With this inventory it should be possible to use the search feature
-for loading tapes.
-debuglevel x:y
-This option will set the debug level and select for which part debug messages
-should be sent to the debug file. In case of problems you should set it to 9:0
-havebarcode 1
-This will force the program to read the barcodes, and don not try to figure out
-if there is an barcode reader available.
-scsitapedev <devicename>
-This device is used to control the tape, read status infos etc.
-tapestatus <filename>
-If this option is given on every eject/move the log pages of the tape device
-will be dumped in this file. There are 2 log pages were you can see how many
-read/write errors (corrected) are processed by the tape
-labelfile <filename>
-This file is used for the mapping from barcode labels to AMANDA volume labels.
-It is used if the changer has a barcode reader. To initialize run amtape show,
-this will add the mapping for the tapes in the magazine.
-eject > 1
-Use the mtio ioctl to eject the tape, use only if the standard (1) does not
-work, and send the debug output (/tmp/amanda/chg-scsi.debug) to th@ant.han.de
-changerident <ident>
-With this it is possible to specify which internal driver to use for
-controlling/error handling of the robot
-tapeident <ident>
-Some as above but for the tape.
-New command line option: -status
-[all|types|robot|sense|ModeSenseRobot|ModeSenseTape|fd]
-<all> will show the result form all options. <types> will list the known driver
-types. <robot> will show the status of all elements (tape/robot/slots..)
-<sense> will show the result from a request sense <ModeSenseRobot> will show
-the sense page from the robot <ModeSenseTape> will show the sense page from the
-tape <fd> will show the devices which are open, and some info about it.
-At the moment changer with tape and robot on the same SCSI id ( but on
-different luns) will run on the following platforms:
-- HP_UX 10.20 - IRIX 6.x - Solaris - Linux - AIX - FreeBSD 3.0/4.0
-Tape and robot on different IDs run native on - Linux - HP-UX 10.20 - Irix 6.x
-- FreeBSD
-Tape and robot on different IDs with special modules run on: Solaris with sst
-kernel module, which is not any longer needed in solaris 2.8. See in the
-contrib/sst directory The configuration on solaris 2.8 with the sgen driver is
-done by creating the file /kernel/drv/sgen.conf
-This file should contain at the beginning the following device-type-config-
-list="changer","sequential"
-This will force the driver to attach only to the devices with type either
-changer (the robot) and sequential (the tape). Next you must tell the driver on
-which id it should check for devices (tape on id 5, robot on id 6 in this
-example),
-name="sgen" class="scsi" target=5 lun=0; name="sgen" class="scsi" target=6
-lun=0;
-This will create the 2 device files /dev/scsi/sequential/c0t5d0 (scsitapedev
-option in chg-scsi.conf) /dev/scsi/changer/c0t6d0 (changer option in chg-
-scsi.conf)
-So the complete sgen.conf looks like: device-type-config-
-list="changer","sequential name="sgen" class="scsi" target=5 lun=0; name="sgen"
-class="scsi" target=6 lun=0;
-For HP you have to create the special device files for the pass throu
-interface. Check if the ctl driver is installed. Example:
-
-  # lsdev -C ctl
-      Character     Block       Driver          Class
-        203          -1         sctl            ctl
-
-Next check on which bus your drives are connected. (ioscan) with the Character
-device num form the lsdev and the card instance from ioscan create the special
-file. Example:
-
-  mknod /dev/scsi/1 c 203 0x001000
-                            ||||
-                            ||| LUN of device
-                            ||SCSI ID of the device
-                            2 digit instance number from ioscan
-
-On FreeBSD 4.0 the syntax for the device files has changed. Now you have to
-tell chg-scsi the bus:target:lun combination. If you for example on your scsi
-bus 0 target 3 an robot the syntax is changerdev 0:3:0 To get this info you can
-use the camcontrol command, <camcontrl devlist> will give you a list of known
-devices. Don't specify dev and scsitapedev in your chg-scsi.conf !!, this will
-not work.
-On Linux you need either sg (generic scsi) as module or it must be compiled
-into the kernel. If the sg driver doses not work try to use the ioctl
-interface. For that you have to undef the LINUX_CHG define in changer-src/scsi-
-linux.c Also you have to change the NORMAL_TIMEOUT in /usr/src/linux/drivers/
-scsi/scsi_ioctl.c from (10 * HZ) to (5 * 60 * HZ). On linux it does not run if
-you are using an aha1542 SCSI controller. The driver can not handle the
-extended request sense.
-On IRIX you find the SCSI pass through interfaces for every device in /dev/
-scsi.
-chg-scsi has been tested/run with the following devices: Exabyte 10h and eliant
-tape HP-Surestore 1200e and C1553A tape BreeceHill Q2.15 (EXB-120) and DLT7000
-tape Powerstor L200 and DLT7000 ARCHIVE Python 28849-XXX TANDBERG TDS 1420 ADIC
-VLS DLT Library
-It is now possible with a changer that has barcode reader to load tapes faster.
-Also amdump will find tapes faster. Every time a tape is labeled the
-information in the labelfile will be updated. To initialize the label mapping
-you can also do an amtape config show. This will put the mapping for all tapes
-in the magazine into the mapping file.
-For all problems please contact th@ant.han.de. Please include in your mail the
-debug file. (/tmp/amanda/chg-scsi.debug)
-
-chg-chio
-
-(new perl script that replaces the original chg-chio written in C) This script
-is based on the FreeBSD version of chio, a program to communicate with the
-jukebox. This script has for the moment only been test with FreeBSD and is
-likely not to work on any other system. Let me know if this is the case and
-send me the output of the chio program for your version of chio. It does not
-restrict the number of tapes, except that if there is only one tape in the
-juke, it is supposed to be in max_slot and not in slot 1. [This is the first
-version of the changer script and I would appreciate all comments on it, at
-nick.hibma@jrc.it. It has been tested only with FreeBSD 2.2.5 and the
-accompanying chio program.]
-
-chg-chs
-
-(formerly chs-changer) A tape changer script very similar to chg-multi, that
-uses the `chs' program to change tapes. As in chg-multi, `tapedev' is ignored.
-`changerfile' names its configuration file, similar to chg-multi.conf.
-`changerdev' will be passed to CHS in a -f command-line switch, unless it is
-set to an empty string or "/dev/null" (watch out for default values!)
-
-chg-rth
-
-(formerly rth-changer) A perl5 script that controls an HPc1553 tape drive via a
-Peripheral Vision Inc. SCSI control subsystem that interprets commands sent on
-the SCSI bus. It expects `tapedev' to specify the tape device to be used.
-`changerfile' and `changerdev' are ignored.
-
-chg-juke
-
-A shell script that uses the Fermilab "juke" software (see http://www.fnal.gov/
-fermitools/, the "juke" link) to control tape chagners. It supports mounting
-multiple tapes for RAIT tapedrive sets, both multiple jukeboxes, or one jukebox
-with multiple tape drives, or combinations. 'juke' must be configured to know
-tape drives by the same name AMANDA calls them. It uses 'changerfile' to track
-AMANDA's current tape state, 'tapedev' must be the tape drive (or RAIT set)
-name, and 'changerdev' is the juke software's name for the changer, or a csh-
-glob that expands to several jukebox names (i.e. "changer{a,b,c}").
-
-chg-rait
-
-A shell script that runs other changers in tandem, and returns a rait:
-{dev1,dev2,...} tape device based on the results of each other changer. So if
-you wanted to have 2 stackers striped with no parity, and you have chg-mtx
-support for your stackers, you would use the follwing changerfile:
-
-
-     nchangers=3
-     tpchanger_1="chg-mtx"
-     changerdev_1="/dev/mtx1"
-     changerfile_1="/some/file1"
-     tapedev_1="/some/dev"
-     tpchanger_2="chg-mtx"
-     changerdev_2="/dev/mtx2"
-     changerfile_2="/some/file2"
-     tapedev_2="/some/dev"
-     tpchanger_3="chg-null"
-     changerdev_3="/dev/null"
-     changerfile_3="/some/file3"
-     tapedev_3="/some/dev"
-
-The third uses the null changer. The tapedev_n entries are only needed if the
-changerfile in question uses them.
-
-chg-disk
-
-Clone of the chg-zd-mtx, but modified to be applied on local directories
-instead of tapes. This changer emulates a robotic that uses virtual tapes
-instead of real ones, where the virtual tapes are real directories on a hard
-disk.
-The directory tree should be:
-
-  slot_root_dir -|
-                 |- info
-                 |- data -> slot1/
-                 |- slot1/
-                 |- slot2/
-                 |- ...
-                 |- slotn/
-
-Where "slot_root_dir" is the tapedev "file:xxx" parameter and "n" the tapecycle
-parameter.
-Please refer to How_to_use_the_AMANDA_file-driver for details of usage.
-
-chg-iomega
-
-This changer script is designed for IOMEGA or JAZZ disks of various sizes as
-well as any other removable disk media. This is a PURELY MANUAL changer. It
-requests insertion of disk media via messages on /dev/tty. So it cannot be used
-via crontab. Make sure you comply with any of the following. - Add statements
-
-          tpchanger "chg-iomega"
-          tapedev "file:<mount_point_of_removable_disk>"
-          (e.g. tapedev "file:/mnt/iomega" )
-          tapetype IOMEGA
-
-
-          define tapetype IOMEGA {
-              comment "IOMega 250 MB floppys"
-              length 250 mbytes
-              filemark 100 kbytes
-              speed 1 mbytes
-          }
-
-to your amanda.conf. - Add entry to /etc/fstab to specify mount point of
-removable disk and make this disk mountable by any user. - Format all disks,
-add a "data" sub directory and label all disks by using amlabel. - Be aware
-that as of version 2.4.4p1, AMANDA can't handle backups that are larger than
-the size of the removable disk media. So make sure /etc/amanda/<backup_set>/
-disklist specifies chunks smaller than the disk size.
-
-chg-null
-
-A trivial changer which loads/unloads on a null: device. Useful with chg-rait
-to throw away a parity stripe by puttin on a null jukebox, or for testing.
--------------------------------------------------------------------------------
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