Mt

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

• tar

External links

• Linux tape backup with mt and tar command - howto
• Howto: Use tar command through network over ssh session
• Tape drives naming convention under Linux
• Howto: Setting up RAID 1 mirroring on a running remote Linux system over ssh connection
• How do I rotate log files?
• Backup shell script to backup selected directories and upload securely (gpg) to FTP server
• http://bash.cyberciti.biz/backup/mybackup.php