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FMS(8)			     AFS Command Reference			FMS(8)

       fms - Determine a tape's	capacity and a tape device's filemark size

       fms -tape <tape special file> [-help]

       fms -t <tape special file> [-h]

       The fms command determines the capacity of the tape currently in	the
       tape device identified by the -tape argument, along with	the size of
       the filemark for	the device. The	filemark is also referred to as	the
       device's	end-of-file (EOF) marker, and can differ for each combination
       of tape and tape	device.

       As the Tape Coordinator writes a	dump, it writes	a filemark between the
       data included from each volume and also tracks the amount of space left
       before the end of the tape (EOT). For some tape devices,	the filemark
       is large	enough (multiple megabytes) that failure to consider it	leads
       the Tape	Coordinator significantly to overestimate the available	space.

       The intended use	of this	command	is to determine	tape capacity and
       filemark	size values that can be	specified in a tape device's entry in
       the /var/openafs/backup/tapeconfig file.	For certain types of tape
       drives, the Tape	Coordinator operates more efficiently when the
       tapeconfig file lists accurate values. For further discussion, see the
       OpenAFS Administration Guide chapter on configuring the Backup System.

       Insert a	tape in	the drive before issuing this command.

       Do not use this command on compressing tape devices in compression mode
       or with tape devices that handle	tapes of multigigabyte (or
       multiterabyte) capacity.	It does	not produce accurate results in	those
       cases.  For alternate suggestions on the	values to record in the
       tapeconfig file for compressing drives, see the OpenAFS Administration
       Guide chapter on	configuring the	Backup System.

       Running the command completely overwrites the tape, so use a blank one
       or one that can be recycled.

       Because it writes filemarks to the complete length of the tape, the
       command can take	from several hours to more than	a day to complete.

       -tape <tape special file>
	   Specifies the UNIX device name of the tape device for which to
	   determine filemark size and the capacity of the tape	it currently
	   contains. The format	varies on different system types, but usually
	   begins with /dev; an	example	is /dev/sd0a.

	   Prints the online help for this command. All	other valid options
	   are ignored.

       The command generates output both on the	standard output	stream and in
       the fms.log file	that it	creates	in the current working directory. The
       output reports the capacity of the tape in the device and the device's
       filemark	size.

       The first few lines of output include status information	about the
       execution of the	command, including such	information as the number of
       blocks and the number of	file marks written to the tape by the command.
       The last	two lines of both screen and file output provide the following

       o   "Tape capacity is number bytes": specifies the size,	in bytes, of
	   the tape in the device.

       o   "File marks are number bytes": specifies the	device's filemark size
	   in bytes.

       The following message indicates that the	fms command interpreter	cannot
       access the tape device. The command halts.

	  Can't	open tape drive	I<device>

       The following message indicates that the	command	interpreter cannot
       create the fms.log log file. Again, the command halts.

	  Can't	open log file

       The following command illustrates the output for	the device called

	  % fms	/dev/rmt1h
	  wrote	block: 130408
	  Finished data	capacity test -	rewinding
	  wrote	1109 blocks, 1109 file marks
	  Finished file	mark test
	  Tape capacity	is 2136604672 bytes
	  File marks are 1910205 bytes

       The following appears in	the fms.log file:

	  fms test started
	  wrote	9230 blocks
	  Finished file	mark test
	  Tape capacity	is 151224320 bytes
	  File marks are 2375680 bytes

       The issuer must be able to insert and write to files in the currently
       working directory, if the fms.log file does not already exist. If it
       already exists, the issuer need only be able to write to	it.

       fms.log(5), tapeconfig(5)

       IBM Corporation 2000. <> All Rights Reserved.

       This documentation is covered by	the IBM	Public License Version 1.0.
       It was converted	from HTML to POD by software written by	Chas Williams
       and Russ	Allbery, based on work by Alf Wachsmann	and Elizabeth Cassell.

OpenAFS				  2016-12-14				FMS(8)


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