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:
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.
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.
Specifies the size of a tape devices filemarks (also called end-of-file
or EOF marks), which is set by the devices 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).|
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 cells 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.
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.
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
backup_addhost(8), backup_dump(8), backup_labeltape(8), backup_savedb(8), butc(8), fms(8)
IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
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