System Administration Guide, Volume 1

How to Copy Files to a Remote Tape Drive (tar and dd)

  1. The following prerequisites must be met to use a remote tape drive:

    • The local hostname (and optionally the username of the user doing the copy) must appear in the remote system's /etc/hosts.equiv file, or the user doing the copy must have his or her home directory accessible on the remote machine, and have the local machine name in $HOME/.rhosts. See hosts.equiv(4) for more information.

    • An entry for the remote system must be in the local system's /etc/inet/hosts file or in the name service hosts file.

  2. To test whether or not you have the appropriate permission to execute a remote command, try the following:

    $ rsh remotehost echo test

    If "test" is echoed back to you, you have permission to execute remote commands. If "Permission denied" is echoed, check your setup as described in step 1 above.

  3. To copy files to a remote tape drive, use the tar and dd commands.

    $ tar cf - files | rsh remotehost dd of=/dev/rmt/n obs=blocksize

    tar cf

    Creates a tape archive and specifies the tape device. 

    - (Hyphen)

    Represents a place holder for the tape device. 


    Identifies files to be copied. 

    | rsh remotehost

    Pipes the tar command's output to a remote shell to copy the files.

    dd of=/dev/rmt/n

    Represents the output device. 


    Represents the blocking factor. 

  4. Remove the tape from the drive and write the names of the files on the tape label.

Example--Copying Files to a Remote Tape Drive (tar and dd)

# tar cvf - * | rsh mercury dd of=/dev/rmt/0 obs=126b
a answers/ 0 tape blocks
a answers/test129 1 tape blocks
a sc.directives/ 0 tape blocks
a sc.directives/sc.190089 1 tape blocks
a tests/ 0 tape blocks
a tests/test131 1 tape blocks
6+9 records in
0+1 records out