[hcoop/debian/openafs.git] / doc / man-pages / pod8 / fms.pod

=head1 NAME

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

=head1 SYNOPSIS

=for html
<div class="synopsis">

B<fms> S<<< B<-tape> <I<tape special file>> >>> [B<-help>]

B<fms> S<<< B<-t> <I<tape special file>> >>> [B<-h>]

=for html
</div>

=head1 DESCRIPTION

The B<fms> command determines the capacity of the tape currently in the
tape device identified by the B<-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
F</usr/afs/backup/tapeconfig> file. For certain types of tape drives, the
Tape Coordinator operates more efficiently when the F<tapeconfig> file
lists accurate values. For further discussion, see the I<OpenAFS
Administration Guide> chapter on configuring the Backup System.

Insert a tape in the drive before issuing this command.

=head1 CAUTIONS

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 B<tapeconfig> file
for compressing drives, see the I<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.

=head1 OPTIONS

=over 4

=item B<-tape> <I<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 F</dev>;
an example is F</dev/sd0a>.

=item B<-help>

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

=back

=head1 OUTPUT

The command generates output both on the standard output stream and in the
F<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 information:

=over 4

=item *

C<Tape capacity is I<number> bytes>: specifies the size, in bytes, of the
tape in the device.

=item *

C<File marks are I<number> bytes>: specifies the device's filemark size in
bytes.

=back

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 F<fms.log> log file. Again, the command halts.

   Can't open log file

=head1 EXAMPLES

The following command illustrates the output for the device called
F</dev/rmt1h>:

   % 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 F<fms.log> file:

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

=head1 PRIVILEGE REQUIRED

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

=head1 SEE ALSO

L<fms.log(5)>,
L<tapeconfig(5)>

=head1 COPYRIGHT

IBM Corporation 2000. <http://www.ibm.com/> 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.
Commit	Line	Data
805e021f CE	1	=head1 NAME
	2
	3	fms - Determine a tape's capacity and a tape device's filemark size
	4
	5	=head1 SYNOPSIS
	6
	7	=for html
	8	<div class="synopsis">
	9
	10	B<fms> S<<< B<-tape> <I<tape special file>> >>> [B<-help>]
	11
	12	B<fms> S<<< B<-t> <I<tape special file>> >>> [B<-h>]
	13
	14	=for html
	15	</div>
	16
	17	=head1 DESCRIPTION
	18
	19	The B<fms> command determines the capacity of the tape currently in the
	20	tape device identified by the B<-tape> argument, along with the size of
	21	the filemark for the device. The filemark is also referred to as the
	22	device's end-of-file (EOF) marker, and can differ for each combination of
	23	tape and tape device.
	24
	25	As the Tape Coordinator writes a dump, it writes a filemark between the
	26	data included from each volume and also tracks the amount of space left
	27	before the end of the tape (EOT). For some tape devices, the filemark is
	28	large enough (multiple megabytes) that failure to consider it leads the
	29	Tape Coordinator significantly to overestimate the available space.
	30
	31	The intended use of this command is to determine tape capacity and
	32	filemark size values that can be specified in a tape device's entry in the
	33	F</usr/afs/backup/tapeconfig> file. For certain types of tape drives, the
	34	Tape Coordinator operates more efficiently when the F<tapeconfig> file
	35	lists accurate values. For further discussion, see the I<OpenAFS
	36	Administration Guide> chapter on configuring the Backup System.
	37
	38	Insert a tape in the drive before issuing this command.
	39
	40	=head1 CAUTIONS
	41
	42	Do not use this command on compressing tape devices in compression mode or
	43	with tape devices that handle tapes of multigigabyte (or multiterabyte)
	44	capacity. It does not produce accurate results in those cases. For
	45	alternate suggestions on the values to record in the B<tapeconfig> file
	46	for compressing drives, see the I<OpenAFS Administration Guide> chapter on
	47	configuring the Backup System.
	48
	49	Running the command completely overwrites the tape, so use a blank one or
	50	one that can be recycled.
	51
	52	Because it writes filemarks to the complete length of the tape, the
	53	command can take from several hours to more than a day to complete.
	54
	55	=head1 OPTIONS
	56
	57	=over 4
	58
	59	=item B<-tape> <I<tape special file>>
	60
	61	Specifies the UNIX device name of the tape device for which to determine
	62	filemark size and the capacity of the tape it currently contains. The
	63	format varies on different system types, but usually begins with F</dev>;
	64	an example is F</dev/sd0a>.
65
66	=item B<-help>
67
68	Prints the online help for this command. All other valid options are
69	ignored.
70
71	=back
72
73	=head1 OUTPUT
74
75	The command generates output both on the standard output stream and in the
76	F<fms.log> file that it creates in the current working directory. The
77	output reports the capacity of the tape in the device and the device's
78	filemark size.
79
80	The first few lines of output include status information about the
81	execution of the command, including such information as the number of
82	blocks and the number of file marks written to the tape by the
83	command. The last two lines of both screen and file output provide the
84	following information:
85
86	=over 4
87
88	=item *
89
90	C<Tape capacity is I<number> bytes>: specifies the size, in bytes, of the
91	tape in the device.
92
93	=item *
94
95	C<File marks are I<number> bytes>: specifies the device's filemark size in
96	bytes.
97
98	=back
99
100	The following message indicates that the fms command interpreter cannot
101	access the tape device. The command halts.
102
103	Can't open tape drive I<device>
104
105	The following message indicates that the command interpreter cannot create
106	the F<fms.log> log file. Again, the command halts.
107
108	Can't open log file
109
110	=head1 EXAMPLES
111
112	The following command illustrates the output for the device called
113	F</dev/rmt1h>:
114
115	% fms /dev/rmt1h
116	wrote block: 130408
117	Finished data capacity test - rewinding
118	wrote 1109 blocks, 1109 file marks
119	Finished file mark test
120	Tape capacity is 2136604672 bytes
121	File marks are 1910205 bytes
122
123	The following appears in the F<fms.log> file:
124
125	fms test started
126	wrote 9230 blocks
127	Finished file mark test
128	Tape capacity is 151224320 bytes
129	File marks are 2375680 bytes
130
131	=head1 PRIVILEGE REQUIRED
132
133	The issuer must be able to insert and write to files in the currently
134	working directory, if the F<fms.log> file does not already exist. If it
135	already exists, the issuer need only be able to write to it.
136
137	=head1 SEE ALSO
138
139	L<fms.log(5)>,
140	L<tapeconfig(5)>
141
142	=head1 COPYRIGHT
143
144	IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
145
146	This documentation is covered by the IBM Public License Version 1.0. It was
147	converted from HTML to POD by software written by Chas Williams and Russ
148	Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.