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1 | =head1 NAME |
2 | ||
3 | tapeconfig - Defines parameters for tape devices and backup data files | |
4 | ||
5 | =head1 DESCRIPTION | |
6 | ||
7 | The F<tapeconfig> file defines basic configuration parameters for all of | |
8 | the tape devices or backup data files available for backup operations on a | |
9 | Tape Coordinator machine. The file is in ASCII format and must reside in | |
10 | the local F</usr/afs/backup> directory. The instruction for each tape | |
11 | device or backup data file appears on its own line and each has the | |
12 | following format: | |
13 | ||
14 | [<capacity> <filemark_size>] <device_name> <port_offset> | |
15 | ||
16 | where | |
17 | ||
18 | =over 4 | |
19 | ||
20 | =item <capacity> | |
21 | ||
22 | Specifies the capacity of the tapes used with a tape device, or the amount | |
23 | of data to write into a backup data file. The Tape Coordinator refers to | |
24 | this value in two circumstances: | |
25 | ||
26 | =over 4 | |
27 | ||
28 | =item * | |
29 | ||
30 | When the capacity field of a tape or backup data file's label is empty | |
31 | (because the tape has never been labeled). The Tape Coordinator records | |
32 | this value on the label and uses it when determining how much data it can | |
33 | write to the tape or file during a B<backup dump> or B<backup savedb> | |
34 | operation. If there is already a capacity value on the label, the Tape | |
35 | Coordinator uses it instead. | |
36 | ||
37 | =item * | |
38 | ||
39 | When the B<-size> argument is omitted the first time the B<backup | |
40 | labeltape> command is used on a given tape or file. The Tape Coordinator | |
41 | copies this value into the label's capacity field. | |
42 | ||
43 | =back | |
44 | ||
45 | The Tape Coordinator uses this capacity value or the one on the Backup | |
46 | System tape label to track how much space remains as it writes data to a | |
47 | tape or backup data file. The appropriate value to record for a tape | |
48 | depends on the size of the tapes usually used in the device and whether it | |
49 | has a compression mode; for suggested values, see the I<OpenAFS | |
50 | Administration Guide> chapter on configuring the Backup System. If using a | |
51 | value obtained from the B<fms> command, reduce it by 10% to 15% before | |
52 | recording it in the file. | |
53 | ||
54 | For a backup data file, it is best to provide a value that helps the Tape | |
55 | Coordinator avoid reaching the end-of-file (EOF) unexpectedly. Make it at | |
56 | least somewhat smaller than the amount of space available on the partition | |
57 | housing the file when the dump operation begins, and never larger than the | |
58 | maximum file size allowed by the operating system. | |
59 | ||
60 | Specify a (positive) integer or decimal value followed by a letter than | |
61 | indicates units, with no intervening space. In a decimal number, the | |
62 | number of digits after the decimal point must not translate to fractions | |
63 | of bytes. The maximum acceptable value is 2048 GB (2 TB). The acceptable | |
64 | units letters are as follows; if the letter is omitted, the default is | |
65 | kilobytes. | |
66 | ||
67 | =over 4 | |
68 | ||
69 | =item * | |
70 | ||
71 | C<k> or C<K> for kilobytes (KB). | |
72 | ||
73 | =item * | |
74 | ||
75 | C<m> or C<M> for megabytes (MB). | |
76 | ||
77 | =item * | |
78 | ||
79 | C<g> or C<G> for gigabytes (GB). | |
80 | ||
81 | =item * | |
82 | ||
83 | C<t> or C<T> for terabytes (TB). | |
84 | ||
85 | =back | |
86 | ||
87 | If this field is omitted, the Tape Coordinator uses the maximum acceptable | |
88 | value (2048 GB or 2 TB). Either leave both this field and the | |
89 | <filemark_size> field empty, or provide a value in both of them. | |
90 | ||
91 | =item <filemark_size> | |
92 | ||
93 | Specifies the size of a tape device's filemarks (also called end-of-file | |
94 | or EOF marks), which is set by the device's manufacturer. In a dump to | |
95 | tape, the Tape Coordinator inserts filemarks at the boundary between the | |
96 | data from each volume, so the filemark size affects how much space is | |
97 | available for actual data. | |
98 | ||
99 | The appropriate value to record for a tape depends on the size of the | |
100 | tapes usually used in the device and whether it has a compression mode; | |
101 | for suggested values, see the I<OpenAFS Administration Guide> chapter on | |
102 | configuring the Backup System. If using a value obtained from the B<fms> | |
103 | command, increase it by 10% to 15% before recording it in the file. | |
104 | ||
105 | For backup data files, record a value of 0 (zero). The Tape Coordinator | |
106 | actually ignores this field for backup data files, because it does not use | |
107 | filemarks when writing to a file. | |
108 | ||
109 | Use the same notation as for the <capacity> field, but note that the | |
110 | default units is bytes rather than kilobytes. The maximum acceptable value | |
111 | is 2048 GB. | |
112 | ||
113 | If this field is empty, the Tape Coordinator uses the value 0 | |
114 | (zero). Either leave both this field and the <capacity> field empty, or | |
115 | provide a value in both of them. | |
116 | ||
117 | =item <device_name> | |
118 | ||
119 | Specifies the complete pathname of the tape device or backup data | |
120 | file. The format of tape device names depends on the operating system, but | |
121 | on UNIX systems device names generally begin with the string F</dev/>. For | |
122 | a backup data file, this field defines the complete pathname; for a | |
123 | discussion of suggested naming conventions see the description of the | |
124 | C<FILE> instruction in L<butc(5)>. | |
125 | ||
126 | =item <port_offset> | |
127 | ||
128 | Specifies the port offset number associated with this combination of Tape | |
129 | Coordinator and tape device or backup data file. | |
130 | ||
131 | Acceptable values are the integers C<0> through C<58510> (the Backup | |
132 | System can track a maximum of 58,511 port offset numbers). Each value | |
133 | must be unique among the cell's Tape Coordinators, but any number of them | |
134 | can be associated with a single machine. Port offset numbers need not be | |
135 | assigned sequentially, and can appear in any order in the F<tapeconfig> | |
136 | file. Assign port offset C<0> to the Tape Coordinator for the tape device | |
137 | or backup data file used most often for backup operations; doing so will | |
138 | allow the operator to omit the B<-portoffset> argument from the largest | |
139 | possible number of B<backup> commands. | |
140 | ||
141 | =back | |
142 | ||
143 | =head1 PRIVILEGE REQUIRED | |
144 | ||
145 | Creating the file requires UNIX C<w> (write) and C<x> (execute) | |
146 | permissions on the F</usr/afs/backup> directory. Editing the file requires | |
147 | UNIX C<w> (write) permission on the file. | |
148 | ||
149 | =head1 EXAMPLES | |
150 | ||
151 | The following example tapeconfig file configures three tape devices and a | |
152 | backup data file. The first device has device name F</dev/rmt/0h>, and is | |
153 | assigned port offset C<0> because it will be the most frequently used | |
154 | device for all backup operations in the cell. Its default tape capacity is | |
155 | 2 GB and filemark size is 1 MB. The F</dev/rmt/3h> drive has half the | |
156 | capacity but a much smaller filemark size; its port offset is C<3>. The | |
157 | third device listed, F</dev/rmt/4h>, has the same capacity and filemark | |
158 | size as the first device and is assigned port offset C<2>. Port offset | |
159 | C<4> is assigned to the backup data file F</dev/FILE>, which is actually a | |
160 | symbolic link to the actual file located elsewhere on the local disk. The | |
161 | Tape Coordinator writes up to 1.5 GB into the file; as recommended, the | |
162 | filemark size is set to zero. | |
163 | ||
164 | 2G 1M /dev/rmt/0h 0 | |
165 | 1g 4k /dev/rmt/3h 3 | |
166 | 2G 1m /dev/rmt/4h 2 | |
167 | 1.5G 0 /dev/FILE 4 | |
168 | ||
169 | =head1 SEE ALSO | |
170 | ||
171 | L<backup_addhost(8)>, | |
172 | L<backup_dump(8)>, | |
173 | L<backup_labeltape(8)>, | |
174 | L<backup_savedb(8)>, | |
175 | L<butc(8)>, | |
176 | L<fms(8)> | |
177 | ||
178 | =head1 COPYRIGHT | |
179 | ||
180 | IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved. | |
181 | ||
182 | This documentation is covered by the IBM Public License Version 1.0. It was | |
183 | converted from HTML to POD by software written by Chas Williams and Russ | |
184 | Allbery, based on work by Alf Wachsmann and Elizabeth Cassell. |