Mt

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The correct title of this article is mt. The initial letter is capitalized due to technical restrictions.

mt is a command used to control and backup data onto magnetic tapes.

Example usage

Note: The default device name should be /dev/st0 (i.e. first SCSI tape device).

  • Rewind tape drive:
% mt -f /dev/st0 rewind
  • Backup directory /data and /home with tar command (z - compressed):
% tar -czf /dev/st0 /data /home
  • Return ("tell") current block:
% mt -f /dev/st0 tell
  • Display list of files on tape drive:
% tar -tzf /dev/st0
  • Restore /data directory:
% cd /
% mt -f /dev/st0 rewind
% tar -xzf /dev/st0 data
  • Unload (i.e. enable eject) the tape:
% mt -f /dev/st0 offline
  • Display status information about the tape unit:
% mt -f /dev/st0 status
  • Erase the tape:
% mt -f /dev/st0 erase
  • Go to end of data:
% mt -f /dev/nst0 eod
  • Goto previous record:
% mt -f /dev/nst0 bsfm 1
  • Forward record:
% mt -f /dev/nst0 fsf 1

Backup via ssh

% tar zcvf - /data | ssh root@www.example.com "cat > /backup/data.tar.gz"
  • Or, using the dd command:
% tar cvzf - /data | ssh root@www.example.com "dd of=/backup/data.tar.gz"
  • Or, backup to a remote tape device:
% tar cvzf - /data | ssh root@www.example.com "cat > /dev/nst0"
  • Also, using the mt command to rewind the tape and then dump to it:
% tar cvzf - /data | ssh root@www.example.com $(mt -f /dev/nst0 rewind; cat > /dev/nst0)$
  • Finally, restore the data over a ssh session:
% ssh root@www.example.com "cat /backup/data.tar.gz" | tar zxvf -

Miscellaneous commands

  • Eject the tape (or CDROM, DVD, etc):
% eject /media/cdrom
  • Close the tray:
% eject -t /media/cdrom
  • Exclude certain files from a tar archive:
% tar -zcvf /home/backup.tar.gz --exclude='foo' --exclude='bar' /home/bob
  • Or, list files to exclude in a file (one filename per line):
% tar -zcvf /home/backup.tar.gz -X exclude.txt /home/bob

Linux tape drives naming conventions

SCSI tape device names

The st driver provides the interface to a variety of SCSI tape devices under Linux.

  • First (auto rewind) SCSI tape device name: /dev/st0
  • Second (auto rewind) SCSI tape device name: /dev/st1
  • First the non-rewind SCSI tape devices: /dev/nst0
  • Second the non-rewind SCSI tape devices: /dev/nst1

IDE tape device names

The ht driver provides the interface to a variety of IDE tape devices under Linux.

  • First (auto rewind) IDE tape device name: /dev/ht0
  • Second (auto rewind) IDE tape device name: /dev/ht1
  • First the non-rewind IDE tape devices: /dev/nht0
  • Second the non-rewind IDE tape devices: /dev/nht1

Main tape types

  • Digital Data Storage (DDS);
  • Digital Audio Tape (DAT); and
  • Digital Linear Tape (DLT)

See also

External links

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