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/lib/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:

           •   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.

           •   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.

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

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

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

           •   "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/lib/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.