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 6.7 (Berkeley) 04/24/91 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 0123456789fusdWn 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 26.Xr rdump 8 27for 28remote backups) . 29A dump that is larger than the output medium is broken into 30multiple volumes of a fixed size; 31the actual size is determined by the tape size and density and/or 32block count options below. 33By default, the same output file name is used for each volume 34after prompting the operator to change media. 35.Pp 36The following options are supported by 37.Nm dump: 38.Bl -tag -width 4n 39.It Cm 0\-9 40Dump levels. 41A level 0, full backup, 42guarantees the entire file system is copied. 43A level number above 0, 44incremental backup, 45tells dump to 46copy all files new or modified since the 47last dump of the same or lower level. The default 48level is 9. 49.It Cm f Op Ar file 50Write the backup to 51.Ar file ; 52.Ar file 53may be a special device file 54like 55.Pa /dev/rmt12 56(a tape drive), 57.Pa /dev/rsd1c 58(an optical drive), 59an ordinary file, 60or 61.Ql Fl 62(the standard output). 63Multiple file names may be given as a single argument separated by commas. 64Each file will be used for one dump volume in the order listed; 65if the dump requires more volumes than the number of names given, 66the last file name will used for all remaining volumes after prompting 67for media changes. 68.It Cm d Ar density 69Set tape density to 70.Ar density . 71The default is 1600BPI. 72.It Cm n 73Whenever 74.Nm dump 75requires operator attention, 76notify all operators in the group 77.Dq operator 78by means similar to a 79.Xr wall 1 . 80.It Cm s Ar feet 81Attempt to caluculate the amount of tape needed 82at a particular density. 83If this amount is exceeded, 84.Nm dump 85prompts for a new tape. It is recommended to be a bit conservative 86on this option. 87The default size is 2300 feet. 88.It Cm u 89Update the file 90.Pa /etc/dumpdates 91after a successful dump. 92The format of 93.Pa /etc/dumpdates 94is readable by people, consisting of one 95free format record per line: 96filesystem name, 97increment level 98and 99.Xr ctime 3 100format dump date. 101There may be only one entry per filesystem at each level. 102The file 103.Pa /etc/dumpdates 104may be edited to change any of the fields, 105if necessary. 106.It Cm W 107.Nm Dump 108tells the operator what file systems need to be dumped. 109This information is gleaned from the files 110.Pa /etc/dumpdates 111and 112.Pa /etc/fstab . 113The 114.Cm W 115option causes 116.Nm dump 117to print out, for each file system in 118.Pa /etc/dumpdates 119the most recent dump date and level, 120and highlights those file systems that should be dumped. 121If the 122.Cm W 123option is set, all other options are ignored, and 124.Nm dump 125exits immediately. 126.It Cm w 127Is like W, but prints only those filesystems which need to be dumped. 128.El 129.Pp 130If no options are specified, 131.Nm dump 132does a level 133.Cm 9u 134to the system's default tape device. 135.Pp 136.Nm Dump 137requires operator intervention on these conditions: 138end of tape, 139end of dump, 140tape write error, 141tape open error or 142disk read error (if there are more than a threshold of 32). 143In addition to alerting all operators implied by the 144.Cm n 145key, 146.Nm dump 147interacts with the operator on 148.Em dump's 149control terminal at times when 150.Nm dump 151can no longer proceed, 152or if something is grossly wrong. 153All questions 154.Nm dump 155poses 156.Em must 157be answered by typing \*(lqyes\*(rq or \*(lqno\*(rq, 158appropriately. 159.Pp 160Since making a dump involves a lot of time and effort for full dumps, 161.Nm dump 162checkpoints itself at the start of each tape volume. 163If writing that volume fails for some reason, 164.Nm dump 165will, 166with operator permission, 167restart itself from the checkpoint 168after the old tape has been rewound and removed, 169and a new tape has been mounted. 170.Pp 171.Nm Dump 172tells the operator what is going on at periodic intervals, 173including usually low estimates of the number of blocks to write, 174the number of tapes it will take, the time to completion, and 175the time to the tape change. 176The output is verbose, 177so that others know that the terminal 178controlling 179.Nm dump 180is busy, 181and will be for some time. 182.Pp 183In the event of a catastrophic disk event, the time required 184to restore all the necessary backup tapes or files to disk 185can be kept to a minimum by staggering the incremental dumps. 186An efficient method of staggering incremental dumps 187to minimize the number of tapes follows: 188.Bl -bullet -offset indent 189.It 190Always start with a level 0 backup, for example: 191.Bd -literal -offset indent 192/etc/dump 0ufds /dev/nrst1 54000 6000 /usr/src 193.Ed 194.Pp 195This should be done at set intervals, say once a month or once every two months, 196and on a set of fresh tapes that is saved forever. 197.It 198After a level 0, dumps of active file 199systems are taken on a daily basis, 200using a modified Tower of Hanoi algorithm, 201with this sequence of dump levels: 202.Bd -literal -offset indent 2033 2 5 4 7 6 9 8 9 9 ... 204.Ed 205.Pp 206For the daily dumps, it should be possible to use a fixed number of tapes 207for each day, used on a weekly basis. 208Each week, a level 1 dump is taken, and 209the daily Hanoi sequence repeats beginning with 3. 210For weekly dumps, another fixed set of tapes per dumped file system is 211used, also on a cyclical basis. 212.El 213.Pp 214After several months or so, the daily and weekly tapes should get 215rotated out of the dump cycle and fresh tapes brought in. 216.Sh FILES 217.Bl -tag -width /etc/dumpdates -compact 218.It Pa /dev/rrp1g 219default filesystem to dump from (system dependent). 220.It Pa /dev/rmt8 221default tape unit to dump to 222.It Pa /etc/dumpdates 223new format dump date record 224.It Pa /etc/fstab 225dump table: file systems and frequency 226.It Pa /etc/group 227to find group 228.Em operator 229.El 230.Sh SEE ALSO 231.Xr rdump 8 , 232.Xr restore 8 , 233.Xr dump 5 , 234.Xr fstab 5 235.Sh DIAGNOSTICS 236Many, and verbose. 237.Pp 238Dump exits with zero status on success. 239Startup errors are indicated with an exit code of 1; 240abnormal termination is indicated with an exit code of 3. 241.Sh BUGS 242.Pp 243Fewer than 32 read errors on the filesystem are ignored. 244Each reel requires a new process, so parent processes for 245reels already written just hang around until the entire tape 246is written. 247.Pp 248.Nm Dump 249with the 250.Cm W 251or 252.Cm w 253options does not report filesystems that have never been recorded 254in 255.Pa /etc/dumpdates , 256even if listed in 257.Pa /etc/fstab . 258.Pp 259It would be nice if 260.Nm dump 261knew about the dump sequence, 262kept track of the tapes scribbled on, 263told the operator which tape to mount when, 264and provided more assistance 265for the operator running 266.Xr restore . 267.Sh HISTORY 268A 269.Nm 270command appeared in Version 6 AT&T UNIX. 271