1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)dump.8 6.12 (Berkeley) 05/11/93 7.\" 8.Dd 9.Dt DUMP 8 10.Os BSD 4 11.Sh NAME 12.Nm dump 13.Nd filesystem backup 14.Sh SYNOPSIS 15.Nm dump 16.Op Cm 0123456789hfusTdWn Op Ar argument ... 17.Op Ar filesystem 18.Sh DESCRIPTION 19.Nm Dump 20examines files 21on a filesystem 22and determines which files 23need to be backed up. These files 24are copied to the given disk, tape or other 25storage medium for safe keeping (see the 26.Cm f 27option below for doing remote backups). 28A dump that is larger than the output medium is broken into 29multiple volumes. 30On most media the size is determined by writing until an 31end-of-media indication is returned. 32On media that cannot reliably return an end-of-media indication 33(such as some cartridge tape drives) 34each volume is of a fixed size; 35the actual size is determined by the tape size and density and/or 36block count options below. 37By default, the same output file name is used for each volume 38after prompting the operator to change media. 39.Pp 40The following options are supported by 41.Nm dump: 42.Bl -tag -width 4n 43.It Cm 0\-9 44Dump levels. 45A level 0, full backup, 46guarantees the entire file system is copied 47(but see also the 48.Cm h 49option below). 50A level number above 0, 51incremental backup, 52tells dump to 53copy all files new or modified since the 54last dump of the same or lower level. The default 55level is 9. 56.It Cm h Ar level 57Honor the user 58.Dq nodump 59flag 60.Dp Dv UF_NODUMP 61only for dumps at or above the given 62.Ar level . 63The default honor level is 1, 64so that incremental backups omit such files 65but full backups retain them. 66.It Cm f Ar file 67Write the backup to 68.Ar file ; 69.Ar file 70may be a special device file 71like 72.Pa /dev/rmt12 73(a tape drive), 74.Pa /dev/rsd1c 75(a disk drive), 76an ordinary file, 77or 78.Ql Fl 79(the standard output). 80Multiple file names may be given as a single argument separated by commas. 81Each file will be used for one dump volume in the order listed; 82if the dump requires more volumes than the number of names given, 83the last file name will used for all remaining volumes after prompting 84for media changes. 85If the name of the file is of the form 86.Dq host:file , 87or 88.Dq user@host:file , 89.Nm dump 90writes to the named file on the remote host using 91.Xr rmt 8 . 92.It Cm d Ar density 93Set tape density to 94.Ar density . 95The default is 1600BPI. 96.It Cm n 97Whenever 98.Nm dump 99requires operator attention, 100notify all operators in the group 101.Dq operator 102by means similar to a 103.Xr wall 1 . 104.It Cm s Ar feet 105Attempt to calculate the amount of tape needed 106at a particular density. 107If this amount is exceeded, 108.Nm dump 109prompts for a new tape. 110It is recommended to be a bit conservative on this option. 111The default tape length is 2300 feet. 112.It Cm u 113Update the file 114.Pa /etc/dumpdates 115after a successful dump. 116The format of 117.Pa /etc/dumpdates 118is readable by people, consisting of one 119free format record per line: 120filesystem name, 121increment level 122and 123.Xr ctime 3 124format dump date. 125There may be only one entry per filesystem at each level. 126The file 127.Pa /etc/dumpdates 128may be edited to change any of the fields, 129if necessary. 130.It Cm T Ar date 131Use the specified date as the starting time for the dump 132instead of the time determined from looking in 133.Pa /etc/dumpdates . 134The format of date is the same as that of 135.Xr ctime 3 . 136This option is useful for automated dump scripts that wish to 137dump over a specific period of time. 138The 139.Cm T 140option is mutually exclusive from the 141.Cm u 142option. 143.It Cm W 144.Nm Dump 145tells the operator what file systems need to be dumped. 146This information is gleaned from the files 147.Pa /etc/dumpdates 148and 149.Pa /etc/fstab . 150The 151.Cm W 152option causes 153.Nm dump 154to print out, for each file system in 155.Pa /etc/dumpdates 156the most recent dump date and level, 157and highlights those file systems that should be dumped. 158If the 159.Cm W 160option is set, all other options are ignored, and 161.Nm dump 162exits immediately. 163.It Cm w 164Is like W, but prints only those filesystems which need to be dumped. 165.El 166.Pp 167.Nm Dump 168requires operator intervention on these conditions: 169end of tape, 170end of dump, 171tape write error, 172tape open error or 173disk read error (if there are more than a threshold of 32). 174In addition to alerting all operators implied by the 175.Cm n 176key, 177.Nm dump 178interacts with the operator on 179.Em dump's 180control terminal at times when 181.Nm dump 182can no longer proceed, 183or if something is grossly wrong. 184All questions 185.Nm dump 186poses 187.Em must 188be answered by typing 189.Dq yes 190or 191.Dq no , 192appropriately. 193.Pp 194Since making a dump involves a lot of time and effort for full dumps, 195.Nm dump 196checkpoints itself at the start of each tape volume. 197If writing that volume fails for some reason, 198.Nm dump 199will, 200with operator permission, 201restart itself from the checkpoint 202after the old tape has been rewound and removed, 203and a new tape has been mounted. 204.Pp 205.Nm Dump 206tells the operator what is going on at periodic intervals, 207including usually low estimates of the number of blocks to write, 208the number of tapes it will take, the time to completion, and 209the time to the tape change. 210The output is verbose, 211so that others know that the terminal 212controlling 213.Nm dump 214is busy, 215and will be for some time. 216.Pp 217In the event of a catastrophic disk event, the time required 218to restore all the necessary backup tapes or files to disk 219can be kept to a minimum by staggering the incremental dumps. 220An efficient method of staggering incremental dumps 221to minimize the number of tapes follows: 222.Bl -bullet -offset indent 223.It 224Always start with a level 0 backup, for example: 225.Bd -literal -offset indent 226/etc/dump 0uf /dev/nrst1 /usr/src 227.Ed 228.Pp 229This should be done at set intervals, say once a month or once every two months, 230and on a set of fresh tapes that is saved forever. 231.It 232After a level 0, dumps of active file 233systems are taken on a daily basis, 234using a modified Tower of Hanoi algorithm, 235with this sequence of dump levels: 236.Bd -literal -offset indent 2373 2 5 4 7 6 9 8 9 9 ... 238.Ed 239.Pp 240For the daily dumps, it should be possible to use a fixed number of tapes 241for each day, used on a weekly basis. 242Each week, a level 1 dump is taken, and 243the daily Hanoi sequence repeats beginning with 3. 244For weekly dumps, another fixed set of tapes per dumped file system is 245used, also on a cyclical basis. 246.El 247.Pp 248After several months or so, the daily and weekly tapes should get 249rotated out of the dump cycle and fresh tapes brought in. 250.Sh FILES 251.Bl -tag -width /etc/dumpdates -compact 252.It Pa /dev/rmt8 253default tape unit to dump to 254.It Pa /etc/dumpdates 255dump date records 256.It Pa /etc/fstab 257dump table: file systems and frequency 258.It Pa /etc/group 259to find group 260.Em operator 261.El 262.Sh SEE ALSO 263.Xr restore 8 , 264.Xr rmt 8 , 265.Xr dump 5 , 266.Xr fstab 5 267.Sh DIAGNOSTICS 268Many, and verbose. 269.Pp 270Dump exits with zero status on success. 271Startup errors are indicated with an exit code of 1; 272abnormal termination is indicated with an exit code of 3. 273.Sh BUGS 274.Pp 275Fewer than 32 read errors on the filesystem are ignored. 276Each reel requires a new process, so parent processes for 277reels already written just hang around until the entire tape 278is written. 279.Pp 280.Nm Dump 281with the 282.Cm W 283or 284.Cm w 285options does not report filesystems that have never been recorded 286in 287.Pa /etc/dumpdates , 288even if listed in 289.Pa /etc/fstab . 290.Pp 291It would be nice if 292.Nm dump 293knew about the dump sequence, 294kept track of the tapes scribbled on, 295told the operator which tape to mount when, 296and provided more assistance 297for the operator running 298.Xr restore . 299.Sh HISTORY 300A 301.Nm dump 302command appeared in Version 6 AT&T UNIX. 303