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na_mt - magnetic tape positioning and control


mt { -f | -t } tapedevice command [ count ]


mt is used to position or control the specified magnetic tape drive supporting the commands listed below. Commands that support a count field allow multiple operations to be performed (the rewind, status, offline, erase and eom commands do not support a count field). mt will output failure messages if the specified tape drive cannot be opened or if the operation fails.

The -f option specifies which tape device to use. Use sysconfig -t to list all tape devices on the filer. -t has the same effect as -f.


eof, weof
Writes count end-of-filemarks beginning at the current position on tape.

Forward spaces over count filemarks. Positions the tape on the end-of-tape side of the filemark.

Backward spaces over count filemarks. Positions the tape on the beginning-of-tape side of the filemark.

Forward spaces count records. Positions the tape on the end-of-tape side of the record(s).

Backward spaces count records. Positions the tape on the beginning-of-tape side of the record(s).

Erases the tape beginning at the current tape position. When the erase completes, the tape is positioned to beginning-of-tape.

Rewinds the tape, positioning the tape to beginning-of-tape.

Displays status information about the tape unit. If you have a tape device that Network Appliance has not qualified, you must use the following command syntax to access the tape device before the filer can register the tape device as a valid clone of a qualified device:

mt -f device status

After the filer accesses the tape device, you can use the sysconfig -t command to display information about the device emulation.

Rewinds the tape and unloads tape media.

Enables or disables display of diagnostic messages from tape driver. Enabling diagnostic messages can be helpful when attempting to diagnose a problem with a tape device. Specifying a count of "1" enables display of diagnostic messages, a count of "0" disables diagnostic messages. Diagnostic messages are disabled by default.

Positions the tape to end of data (end of media if tape is full).


The following example uses mt to display status information for the no-rewind tape device, unit zero, highest format (density):

toaster> mt -f nrst0a status

  Tape drive: Exabyte 8505 8mm
      Status: ready, write enabled
      Format: EXB-8500C (w/compression)
      fileno = 0  blockno = 0  resid = 0

To skip over a previously created dump file to append a dump onto a no-rewind tape device, use the fsf (forward space file) command:

toaster> mt -f nrst0a fsf 1


In takeover mode, the failed filer has no access to its tape devices. If you enter the mt command in partner mode, the command uses the tape devices on the live filer.


na_partner(1), na_sysconfig(1), na_tape(4).

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