| 1 | .\" Copyright (c) 1980, 1991 Regents of the University of California. |
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| 32 | .\" @(#)dump.8 6.8 (Berkeley) 6/17/91 |
| 33 | .\" |
| 34 | .\" $Header: /b/source/CVS/src/sbin/dump/dump.8,v 1.3 1993/03/23 00:27:01 cgd Exp $ |
| 35 | .\" |
| 36 | .Dd June 17, 1991 |
| 37 | .Dt DUMP 8 |
| 38 | .Os BSD 4 |
| 39 | .Sh NAME |
| 40 | .Nm dump |
| 41 | .Nd filesystem backup |
| 42 | .Sh SYNOPSIS |
| 43 | .Nm dump |
| 44 | .Op Cm 0123456789fusdWn Op Ar argument ... |
| 45 | .Op Ar filesystem |
| 46 | .Sh DESCRIPTION |
| 47 | .Nm Dump |
| 48 | examines files |
| 49 | on a filesystem |
| 50 | and determines which files |
| 51 | need to be backed up. These files |
| 52 | are copied to the given disk, tape or other |
| 53 | storage medium for safe keeping (see |
| 54 | .Xr rdump 8 |
| 55 | for |
| 56 | remote backups) . |
| 57 | A dump that is larger than the output medium is broken into |
| 58 | multiple volumes of a fixed size; |
| 59 | the actual size is determined by the tape size and density and/or |
| 60 | block count options below. |
| 61 | By default, the same output file name is used for each volume |
| 62 | after prompting the operator to change media. |
| 63 | .Pp |
| 64 | The following options are supported by |
| 65 | .Nm dump: |
| 66 | .Bl -tag -width 4n |
| 67 | .It Cm 0\-9 |
| 68 | Dump levels. |
| 69 | A level 0, full backup, |
| 70 | guarantees the entire file system is copied. |
| 71 | A level number above 0, |
| 72 | incremental backup, |
| 73 | tells dump to |
| 74 | copy all files new or modified since the |
| 75 | last dump of the same or lower level. The default |
| 76 | level is 9. |
| 77 | .It Cm f Op Ar file |
| 78 | Write the backup to |
| 79 | .Ar file ; |
| 80 | .Ar file |
| 81 | may be a special device file |
| 82 | like |
| 83 | .Pa /dev/rmt12 |
| 84 | (a tape drive), |
| 85 | .Pa /dev/rsd1c |
| 86 | (an optical drive), |
| 87 | an ordinary file, |
| 88 | or |
| 89 | .Ql Fl |
| 90 | (the standard output). |
| 91 | Multiple file names may be given as a single argument separated by commas. |
| 92 | Each file will be used for one dump volume in the order listed; |
| 93 | if the dump requires more volumes than the number of names given, |
| 94 | the last file name will used for all remaining volumes after prompting |
| 95 | for media changes. |
| 96 | .It Cm d Ar density |
| 97 | Set tape density to |
| 98 | .Ar density . |
| 99 | The default is 1600BPI. |
| 100 | .It Cm n |
| 101 | Whenever |
| 102 | .Nm dump |
| 103 | requires operator attention, |
| 104 | notify all operators in the group |
| 105 | .Dq operator |
| 106 | by means similar to a |
| 107 | .Xr wall 1 . |
| 108 | .It Cm s Ar feet |
| 109 | Attempt to caluculate the amount of tape needed |
| 110 | at a particular density. |
| 111 | If this amount is exceeded, |
| 112 | .Nm dump |
| 113 | prompts for a new tape. |
| 114 | It is recommended to be a bit conservative on this option. |
| 115 | The default tape length is 2300 feet. |
| 116 | .It Cm B Ar blocks |
| 117 | Set the size of the dump file to the specified number of 1024-byte blocks, |
| 118 | superceding the tape size and density. |
| 119 | .It Cm u |
| 120 | Update the file |
| 121 | .Pa /etc/dumpdates |
| 122 | after a successful dump. |
| 123 | The format of |
| 124 | .Pa /etc/dumpdates |
| 125 | is readable by people, consisting of one |
| 126 | free format record per line: |
| 127 | filesystem name, |
| 128 | increment level |
| 129 | and |
| 130 | .Xr ctime 3 |
| 131 | format dump date. |
| 132 | There may be only one entry per filesystem at each level. |
| 133 | The file |
| 134 | .Pa /etc/dumpdates |
| 135 | may be edited to change any of the fields, |
| 136 | if necessary. |
| 137 | .It Cm W |
| 138 | .Nm Dump |
| 139 | tells the operator what file systems need to be dumped. |
| 140 | This information is gleaned from the files |
| 141 | .Pa /etc/dumpdates |
| 142 | and |
| 143 | .Pa /etc/fstab . |
| 144 | The |
| 145 | .Cm W |
| 146 | option causes |
| 147 | .Nm dump |
| 148 | to print out, for each file system in |
| 149 | .Pa /etc/dumpdates |
| 150 | the most recent dump date and level, |
| 151 | and highlights those file systems that should be dumped. |
| 152 | If the |
| 153 | .Cm W |
| 154 | option is set, all other options are ignored, and |
| 155 | .Nm dump |
| 156 | exits immediately. |
| 157 | .It Cm w |
| 158 | Is like W, but prints only those filesystems which need to be dumped. |
| 159 | .El |
| 160 | .Pp |
| 161 | .Nm Dump |
| 162 | requires operator intervention on these conditions: |
| 163 | end of tape, |
| 164 | end of dump, |
| 165 | tape write error, |
| 166 | tape open error or |
| 167 | disk read error (if there are more than a threshold of 32). |
| 168 | In addition to alerting all operators implied by the |
| 169 | .Cm n |
| 170 | key, |
| 171 | .Nm dump |
| 172 | interacts with the operator on |
| 173 | .Em dump's |
| 174 | control terminal at times when |
| 175 | .Nm dump |
| 176 | can no longer proceed, |
| 177 | or if something is grossly wrong. |
| 178 | All questions |
| 179 | .Nm dump |
| 180 | poses |
| 181 | .Em must |
| 182 | be answered by typing \*(lqyes\*(rq or \*(lqno\*(rq, |
| 183 | appropriately. |
| 184 | .Pp |
| 185 | Since making a dump involves a lot of time and effort for full dumps, |
| 186 | .Nm dump |
| 187 | checkpoints itself at the start of each tape volume. |
| 188 | If writing that volume fails for some reason, |
| 189 | .Nm dump |
| 190 | will, |
| 191 | with operator permission, |
| 192 | restart itself from the checkpoint |
| 193 | after the old tape has been rewound and removed, |
| 194 | and a new tape has been mounted. |
| 195 | .Pp |
| 196 | .Nm Dump |
| 197 | tells the operator what is going on at periodic intervals, |
| 198 | including usually low estimates of the number of blocks to write, |
| 199 | the number of tapes it will take, the time to completion, and |
| 200 | the time to the tape change. |
| 201 | The output is verbose, |
| 202 | so that others know that the terminal |
| 203 | controlling |
| 204 | .Nm dump |
| 205 | is busy, |
| 206 | and will be for some time. |
| 207 | .Pp |
| 208 | In the event of a catastrophic disk event, the time required |
| 209 | to restore all the necessary backup tapes or files to disk |
| 210 | can be kept to a minimum by staggering the incremental dumps. |
| 211 | An efficient method of staggering incremental dumps |
| 212 | to minimize the number of tapes follows: |
| 213 | .Bl -bullet -offset indent |
| 214 | .It |
| 215 | Always start with a level 0 backup, for example: |
| 216 | .Bd -literal -offset indent |
| 217 | /etc/dump 0ufds /dev/nrst1 54000 6000 /usr/src |
| 218 | .Ed |
| 219 | .Pp |
| 220 | This should be done at set intervals, say once a month or once every two months, |
| 221 | and on a set of fresh tapes that is saved forever. |
| 222 | .It |
| 223 | After a level 0, dumps of active file |
| 224 | systems are taken on a daily basis, |
| 225 | using a modified Tower of Hanoi algorithm, |
| 226 | with this sequence of dump levels: |
| 227 | .Bd -literal -offset indent |
| 228 | 3 2 5 4 7 6 9 8 9 9 ... |
| 229 | .Ed |
| 230 | .Pp |
| 231 | For the daily dumps, it should be possible to use a fixed number of tapes |
| 232 | for each day, used on a weekly basis. |
| 233 | Each week, a level 1 dump is taken, and |
| 234 | the daily Hanoi sequence repeats beginning with 3. |
| 235 | For weekly dumps, another fixed set of tapes per dumped file system is |
| 236 | used, also on a cyclical basis. |
| 237 | .El |
| 238 | .Pp |
| 239 | After several months or so, the daily and weekly tapes should get |
| 240 | rotated out of the dump cycle and fresh tapes brought in. |
| 241 | .Sh FILES |
| 242 | .Bl -tag -width /etc/dumpdates -compact |
| 243 | .It Pa /dev/rrp1g |
| 244 | default filesystem to dump from (system dependent). |
| 245 | .It Pa /dev/rmt8 |
| 246 | default tape unit to dump to |
| 247 | .It Pa /etc/dumpdates |
| 248 | new format dump date record |
| 249 | .It Pa /etc/fstab |
| 250 | dump table: file systems and frequency |
| 251 | .It Pa /etc/group |
| 252 | to find group |
| 253 | .Em operator |
| 254 | .El |
| 255 | .Sh SEE ALSO |
| 256 | .Xr rdump 8 , |
| 257 | .Xr restore 8 , |
| 258 | .Xr dump 5 , |
| 259 | .Xr fstab 5 |
| 260 | .Sh DIAGNOSTICS |
| 261 | Many, and verbose. |
| 262 | .Pp |
| 263 | Dump exits with zero status on success. |
| 264 | Startup errors are indicated with an exit code of 1; |
| 265 | abnormal termination is indicated with an exit code of 3. |
| 266 | .Sh BUGS |
| 267 | .Pp |
| 268 | Fewer than 32 read errors on the filesystem are ignored. |
| 269 | Each reel requires a new process, so parent processes for |
| 270 | reels already written just hang around until the entire tape |
| 271 | is written. |
| 272 | .Pp |
| 273 | .Nm Dump |
| 274 | with the |
| 275 | .Cm W |
| 276 | or |
| 277 | .Cm w |
| 278 | options does not report filesystems that have never been recorded |
| 279 | in |
| 280 | .Pa /etc/dumpdates , |
| 281 | even if listed in |
| 282 | .Pa /etc/fstab . |
| 283 | .Pp |
| 284 | It would be nice if |
| 285 | .Nm dump |
| 286 | knew about the dump sequence, |
| 287 | kept track of the tapes scribbled on, |
| 288 | told the operator which tape to mount when, |
| 289 | and provided more assistance |
| 290 | for the operator running |
| 291 | .Xr restore . |
| 292 | .Sh HISTORY |
| 293 | A |
| 294 | .Nm |
| 295 | command appeared in Version 6 AT&T UNIX. |