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Specifying the tape file size

You can specify the maximum size of the tape file in terms of tape blocks in a dump command. If you do a remote backup or plan to restore the backup on a system other than the storage system that was backed up, you might need to specify a tape file size.

About this task

Suppose you want the maximum tape file to be 2 GB; you must specify 2,097,151. This implies that the largest tape file can contain 2,097,151 tape blocks, which are 1 kilobyte each. The tape file size must be equal to or greater than the blocking factor; otherwise, the dump process terminates.

Some systems support only tape files of a limited size; for example, some Solaris systems do not support tape files larger than 2 GB.


  1. To specify a tape file size, include the B option in the dump command line.
  2. Include the tape file size, in KB, in the dump command as a parameter to the B option.

    The size applies to all tape files in the backup.


The following command backs up the /vol/vol0 volume using a tape file size of 2,097,151, so that a tape file is no larger than 2 GB:

dump 0fB rst0a 2097151 /vol/vol0

The following list describes the elements of the command line:
Does a full backup.
Specifies that a tape device is supplied in the command line.
Specifies that the file size is given in the command line.
The tape drive rewinds the tape.
The file size is 2,097,151 KB.
The volume to be backed up.