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TAPECONFIG(5)		      AFS File Reference		 TAPECONFIG(5)

NAME
       tapeconfig - Defines parameters for tape	devices	and backup data	files

DESCRIPTION
       The tapeconfig file defines basic configuration parameters for all of
       the tape	devices	or backup data files available for backup operations
       on a Tape Coordinator machine. The file is in ASCII format and must
       reside in the local /var/openafs/backup directory. The instruction for
       each tape device	or backup data file appears on its own line and	each
       has the following format:

	  [<capacity> <filemark_size>] <device_name> <port_offset>

       where

       <capacity>
	   Specifies the capacity of the tapes used with a tape	device,	or the
	   amount of data to write into	a backup data file. The	Tape
	   Coordinator refers to this value in two circumstances:

	   o   When the	capacity field of a tape or backup data	file's label
	       is empty	(because the tape has never been labeled). The Tape
	       Coordinator records this	value on the label and uses it when
	       determining how much data it can	write to the tape or file
	       during a	backup dump or backup savedb operation.	If there is
	       already a capacity value	on the label, the Tape Coordinator
	       uses it instead.

	   o   When the	-size argument is omitted the first time the backup
	       labeltape command is used on a given tape or file.  The Tape
	       Coordinator copies this value into the label's capacity field.

	   The Tape Coordinator	uses this capacity value or the	one on the
	   Backup System tape label to track how much space remains as it
	   writes data to a tape or backup data	file. The appropriate value to
	   record for a	tape depends on	the size of the	tapes usually used in
	   the device and whether it has a compression mode; for suggested
	   values, see the OpenAFS Administration Guide	chapter	on configuring
	   the Backup System. If using a value obtained	from the fms command,
	   reduce it by	10% to 15% before recording it in the file.

	   For a backup	data file, it is best to provide a value that helps
	   the Tape Coordinator	avoid reaching the end-of-file (EOF)
	   unexpectedly. Make it at least somewhat smaller than	the amount of
	   space available on the partition housing the	file when the dump
	   operation begins, and never larger than the maximum file size
	   allowed by the operating system.

	   Specify a (positive)	integer	or decimal value followed by a letter
	   than	indicates units, with no intervening space. In a decimal
	   number, the number of digits	after the decimal point	must not
	   translate to	fractions of bytes. The	maximum	acceptable value is
	   2048	GB (2 TB). The acceptable units	letters	are as follows;	if the
	   letter is omitted, the default is kilobytes.

	   o   "k" or "K" for kilobytes	(KB).

	   o   "m" or "M" for megabytes	(MB).

	   o   "g" or "G" for gigabytes	(GB).

	   o   "t" or "T" for terabytes	(TB).

	   If this field is omitted, the Tape Coordinator uses the maximum
	   acceptable value (2048 GB or	2 TB). Either leave both this field
	   and the <filemark_size> field empty,	or provide a value in both of
	   them.

       <filemark_size>
	   Specifies the size of a tape	device's filemarks (also called	end-
	   of-file or EOF marks), which	is set by the device's manufacturer.
	   In a	dump to	tape, the Tape Coordinator inserts filemarks at	the
	   boundary between the	data from each volume, so the filemark size
	   affects how much space is available for actual data.

	   The appropriate value to record for a tape depends on the size of
	   the tapes usually used in the device	and whether it has a
	   compression mode; for suggested values, see the OpenAFS
	   Administration Guide	chapter	on configuring the Backup System. If
	   using a value obtained from the fms command,	increase it by 10% to
	   15% before recording	it in the file.

	   For backup data files, record a value of 0 (zero). The Tape
	   Coordinator actually	ignores	this field for backup data files,
	   because it does not use filemarks when writing to a file.

	   Use the same	notation as for	the <capacity> field, but note that
	   the default units is	bytes rather than kilobytes. The maximum
	   acceptable value is 2048 GB.

	   If this field is empty, the Tape Coordinator	uses the value 0
	   (zero). Either leave	both this field	and the	<capacity> field
	   empty, or provide a value in	both of	them.

       <device_name>
	   Specifies the complete pathname of the tape device or backup	data
	   file. The format of tape device names depends on the	operating
	   system, but on UNIX systems device names generally begin with the
	   string /dev/. For a backup data file, this field defines the
	   complete pathname; for a discussion of suggested naming conventions
	   see the description of the "FILE" instruction in butc(5).

       <port_offset>
	   Specifies the port offset number associated with this combination
	   of Tape Coordinator and tape	device or backup data file.

	   Acceptable values are the integers 0	through	58510 (the Backup
	   System can track a maximum of 58,511	port offset numbers).  Each
	   value must be unique	among the cell's Tape Coordinators, but	any
	   number of them can be associated with a single machine. Port	offset
	   numbers need	not be assigned	sequentially, and can appear in	any
	   order in the	tapeconfig file. Assign	port offset 0 to the Tape
	   Coordinator for the tape device or backup data file used most often
	   for backup operations; doing	so will	allow the operator to omit the
	   -portoffset argument	from the largest possible number of backup
	   commands.

PRIVILEGE REQUIRED
       Creating	the file requires UNIX "w" (write) and "x" (execute)
       permissions on the /var/openafs/backup directory. Editing the file
       requires	UNIX "w" (write) permission on the file.

EXAMPLES
       The following example tapeconfig	file configures	three tape devices and
       a backup	data file. The first device has	device name /dev/rmt/0h, and
       is assigned port	offset 0 because it will be the	most frequently	used
       device for all backup operations	in the cell. Its default tape capacity
       is 2 GB and filemark size is 1 MB. The /dev/rmt/3h drive	has half the
       capacity	but a much smaller filemark size; its port offset is 3.	The
       third device listed, /dev/rmt/4h, has the same capacity and filemark
       size as the first device	and is assigned	port offset 2. Port offset 4
       is assigned to the backup data file /dev/FILE, which is actually	a
       symbolic	link to	the actual file	located	elsewhere on the local disk.
       The Tape	Coordinator writes up to 1.5 GB	into the file; as recommended,
       the filemark size is set	to zero.

	  2G 1M	/dev/rmt/0h 0
	  1g 4k	/dev/rmt/3h 3
	  2G 1m	/dev/rmt/4h 2
	  1.5G 0 /dev/FILE 4

SEE ALSO
       backup_addhost(8), backup_dump(8), backup_labeltape(8),
       backup_savedb(8), butc(8), fms(8)

COPYRIGHT
       IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.

       This documentation is covered by	the IBM	Public License Version 1.0.
       It was converted	from HTML to POD by software written by	Chas Williams
       and Russ	Allbery, based on work by Alf Wachsmann	and Elizabeth Cassell.

OpenAFS				  2016-12-14			 TAPECONFIG(5)

NAME | DESCRIPTION | PRIVILEGE REQUIRED | EXAMPLES | SEE ALSO | COPYRIGHT

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