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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.
-
fsf
- Forward spaces over count filemarks. Positions
the tape on the end-of-tape side of the
filemark.
-
bsf
- Backward spaces over count filemarks. Positions
the tape on the beginning-of-tape side
of the filemark.
-
fsr
- Forward spaces count records. Positions the
tape on the end-of-tape side of the
record(s).
-
bsr
- Backward spaces count records. Positions the
tape on the beginning-of-tape side of the
record(s).
-
erase
- Erases the tape beginning at the current tape
position. When the erase completes, the tape
is positioned to beginning-of-tape.
-
rewind
- Rewinds the tape, positioning the tape to
beginning-of-tape.
-
status
- 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.
-
offline
- Rewinds the tape and unloads tape media.
-
diag
- 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.
-
eom
- 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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