1.\" Copyright (c) 1980, 1991, 1993 2.\" Regents of the University of California. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 15.\" This product includes software developed by the University of 16.\" California, Berkeley and its contributors. 17.\" 4. Neither the name of the University nor the names of its contributors 18.\" may be used to endorse or promote products derived from this software 19.\" without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" @(#)dump.8 8.1 (Berkeley) 6/16/93 34.\" $FreeBSD$ 35.\" 36.Dd June 16, 1993 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 0123456789BTWabcdfhnsu Op Ar argument ... 45.Op Ar filesystem 46.Sh DESCRIPTION 47.Nm Dump 48examines files 49on a filesystem 50and determines which files 51need to be backed up. These files 52are copied to the given disk, tape or other 53storage medium for safe keeping (see the 54.Cm f 55option below for doing remote backups). 56A dump that is larger than the output medium is broken into 57multiple volumes. 58On most media the size is determined by writing until an 59end-of-media indication is returned. This can be enforced 60by using the 61.Cm a 62option. 63.Pp 64On media that cannot reliably return an end-of-media indication 65(such as some cartridge tape drives) 66each volume is of a fixed size; 67the actual size is determined by the tape size and density and/or 68block count options below. 69By default, the same output file name is used for each volume 70after prompting the operator to change media. 71.Pp 72The following options are supported by 73.Nm dump: 74.Bl -tag -width 4n 75.It Cm 0\-9 76Dump levels. 77A level 0, full backup, 78guarantees the entire file system is copied 79(but see also the 80.Cm h 81option below). 82A level number above 0, 83incremental backup, 84tells dump to 85copy all files new or modified since the 86last dump of the same or lower level. The default 87level is 9. 88.It Cm B Ar records 89The number of dump records per volume. 90This option overrides the calculation of tape size 91based on length and density. 92.It Cm a 93.Dq auto-size . 94Bypass all tape length considerations, and enforce writing 95until an end-of-media indication is returned. This fits best 96for most modern tape drives. Use of this option is particularly 97recommended when appending to an existing tape, or using a tape 98drive with hardware compression (where you can never be sure about 99the compression ratio). 100.It Cm b Ar blocksize 101The number of kilobytes per dump record. 102.It Cm c 103Change the defaults for use with a cartridge tape drive, with a density 104of 8000 bpi, and a length of 1700 feet. 105.It Cm h Ar level 106Honor the user 107.Dq nodump 108flag 109.Dp Dv UF_NODUMP 110only for dumps at or above the given 111.Ar level . 112The default honor level is 1, 113so that incremental backups omit such files 114but full backups retain them. 115.It Cm f Ar file 116Write the backup to 117.Ar file ; 118.Ar file 119may be a special device file 120like 121.Pa /dev/rst0 122(a tape drive), 123.Pa /dev/rfd1 124(a floppy disk drive), 125an ordinary file, 126or 127.Ql Fl 128(the standard output). 129Multiple file names may be given as a single argument separated by commas. 130Each file will be used for one dump volume in the order listed; 131if the dump requires more volumes than the number of names given, 132the last file name will used for all remaining volumes after prompting 133for media changes. 134If the name of the file is of the form 135.Dq host:file , 136or 137.Dq user@host:file , 138.Nm dump 139writes to the named file on the remote host using 140.Xr rmt 8 . 141The default path name of the remote 142.Xr rmt 8 143program is 144.\" rmt path, is the path on the remote host 145.Pa /etc/rmt ; 146this can be overridden by the environment variable 147.Ev RMT . 148.It Cm d Ar density 149Set tape density to 150.Ar density . 151The default is 1600BPI. 152.It Cm n 153Whenever 154.Nm dump 155requires operator attention, 156notify all operators in the group 157.Dq operator 158by means similar to a 159.Xr wall 1 . 160.It Cm s Ar feet 161Attempt to calculate the amount of tape needed 162at a particular density. 163If this amount is exceeded, 164.Nm dump 165prompts for a new tape. 166It is recommended to be a bit conservative on this option. 167The default tape length is 2300 feet. 168.It Cm u 169Update the file 170.Pa /etc/dumpdates 171after a successful dump. 172The format of 173.Pa /etc/dumpdates 174is readable by people, consisting of one 175free format record per line: 176filesystem name, 177increment level 178and 179.Xr ctime 3 180format dump date. 181There may be only one entry per filesystem at each level. 182The file 183.Pa /etc/dumpdates 184may be edited to change any of the fields, 185if necessary. 186.It Cm T Ar date 187Use the specified date as the starting time for the dump 188instead of the time determined from looking in 189.Pa /etc/dumpdates . 190The format of date is the same as that of 191.Xr ctime 3 . 192This option is useful for automated dump scripts that wish to 193dump over a specific period of time. 194The 195.Cm T 196option is mutually exclusive from the 197.Cm u 198option. 199.It Cm W 200.Nm Dump 201tells the operator what file systems need to be dumped. 202This information is gleaned from the files 203.Pa /etc/dumpdates 204and 205.Pa /etc/fstab . 206The 207.Cm W 208option causes 209.Nm dump 210to print out, for each file system in 211.Pa /etc/dumpdates 212the most recent dump date and level, 213and highlights those file systems that should be dumped. 214If the 215.Cm W 216option is set, all other options are ignored, and 217.Nm dump 218exits immediately. 219.It Cm w 220Is like W, but prints only those filesystems which need to be dumped. 221.El 222.Pp 223.Nm Dump 224requires operator intervention on these conditions: 225end of tape, 226end of dump, 227tape write error, 228tape open error or 229disk read error (if there are more than a threshold of 32). 230In addition to alerting all operators implied by the 231.Cm n 232key, 233.Nm dump 234interacts with the operator on 235.Em dump's 236control terminal at times when 237.Nm dump 238can no longer proceed, 239or if something is grossly wrong. 240All questions 241.Nm dump 242poses 243.Em must 244be answered by typing 245.Dq yes 246or 247.Dq no , 248appropriately. 249.Pp 250Since making a dump involves a lot of time and effort for full dumps, 251.Nm dump 252checkpoints itself at the start of each tape volume. 253If writing that volume fails for some reason, 254.Nm dump 255will, 256with operator permission, 257restart itself from the checkpoint 258after the old tape has been rewound and removed, 259and a new tape has been mounted. 260.Pp 261.Nm Dump 262tells the operator what is going on at periodic intervals, 263including usually low estimates of the number of blocks to write, 264the number of tapes it will take, the time to completion, and 265the time to the tape change. 266The output is verbose, 267so that others know that the terminal 268controlling 269.Nm dump 270is busy, 271and will be for some time. 272.Pp 273In the event of a catastrophic disk event, the time required 274to restore all the necessary backup tapes or files to disk 275can be kept to a minimum by staggering the incremental dumps. 276An efficient method of staggering incremental dumps 277to minimize the number of tapes follows: 278.Bl -bullet -offset indent 279.It 280Always start with a level 0 backup, for example: 281.Bd -literal -offset indent 282/sbin/dump 0uf /dev/nrst0 /usr/src 283.Ed 284.Pp 285This should be done at set intervals, say once a month or once every two months, 286and on a set of fresh tapes that is saved forever. 287.It 288After a level 0, dumps of active file 289systems are taken on a daily basis, 290using a modified Tower of Hanoi algorithm, 291with this sequence of dump levels: 292.Bd -literal -offset indent 2933 2 5 4 7 6 9 8 9 9 ... 294.Ed 295.Pp 296For the daily dumps, it should be possible to use a fixed number of tapes 297for each day, used on a weekly basis. 298Each week, a level 1 dump is taken, and 299the daily Hanoi sequence repeats beginning with 3. 300For weekly dumps, another fixed set of tapes per dumped file system is 301used, also on a cyclical basis. 302.El 303.Pp 304After several months or so, the daily and weekly tapes should get 305rotated out of the dump cycle and fresh tapes brought in. 306.Sh ENVIRONMENT 307The environment variable 308.Ev RMT 309will be used to determine the pathname of the remote 310.Xr rmt 8 311program. 312.Sh FILES 313.Bl -tag -width /etc/dumpdates -compact 314.It Pa /dev/rst0 315default tape unit to dump to 316.It Pa /etc/dumpdates 317dump date records 318.It Pa /etc/fstab 319dump table: file systems and frequency 320.It Pa /etc/group 321to find group 322.Em operator 323.El 324.Sh SEE ALSO 325.Xr dump 5 , 326.Xr fstab 5 , 327.Xr ft 8 , 328.Xr restore 8 , 329.Xr rmt 8 330.Sh DIAGNOSTICS 331Many, and verbose. 332.Pp 333Dump exits with zero status on success. 334Startup errors are indicated with an exit code of 1; 335abnormal termination is indicated with an exit code of 3. 336.Sh BUGS 337.Pp 338Fewer than 32 read errors on the filesystem are ignored. 339Each reel requires a new process, so parent processes for 340reels already written just hang around until the entire tape 341is written. 342.Pp 343Currently, 344.Xr physio 9 345slices all requests into chunks of 64 KB. Therefore, it is 346impossible to use a larger tape blocksize, so 347.Nm dump 348will prevent this from happening. 349.Pp 350.Nm Dump 351with the 352.Cm W 353or 354.Cm w 355options does not report filesystems that have never been recorded 356in 357.Pa /etc/dumpdates , 358even if listed in 359.Pa /etc/fstab . 360.Pp 361It would be nice if 362.Nm dump 363knew about the dump sequence, 364kept track of the tapes scribbled on, 365told the operator which tape to mount when, 366and provided more assistance 367for the operator running 368.Xr restore . 369.Pp 370.Nm dump 371cannot do remote backups without being run as root, due to its 372security history. This will be fixed in a later version of FreeBSD. 373Presently, it work if you set it setuid (like it used to be), but this 374might constitute a security risk. 375.Sh HISTORY 376A 377.Nm dump 378command appeared in 379.At v6 . 380