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 6.8 (Berkeley) 06/17/91 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. 86It is recommended to be a bit conservative on this option. 87The default tape length 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 130.Nm Dump 131requires operator intervention on these conditions: 132end of tape, 133end of dump, 134tape write error, 135tape open error or 136disk read error (if there are more than a threshold of 32). 137In addition to alerting all operators implied by the 138.Cm n 139key, 140.Nm dump 141interacts with the operator on 142.Em dump's 143control terminal at times when 144.Nm dump 145can no longer proceed, 146or if something is grossly wrong. 147All questions 148.Nm dump 149poses 150.Em must 151be answered by typing \*(lqyes\*(rq or \*(lqno\*(rq, 152appropriately. 153.Pp 154Since making a dump involves a lot of time and effort for full dumps, 155.Nm dump 156checkpoints itself at the start of each tape volume. 157If writing that volume fails for some reason, 158.Nm dump 159will, 160with operator permission, 161restart itself from the checkpoint 162after the old tape has been rewound and removed, 163and a new tape has been mounted. 164.Pp 165.Nm Dump 166tells the operator what is going on at periodic intervals, 167including usually low estimates of the number of blocks to write, 168the number of tapes it will take, the time to completion, and 169the time to the tape change. 170The output is verbose, 171so that others know that the terminal 172controlling 173.Nm dump 174is busy, 175and will be for some time. 176.Pp 177In the event of a catastrophic disk event, the time required 178to restore all the necessary backup tapes or files to disk 179can be kept to a minimum by staggering the incremental dumps. 180An efficient method of staggering incremental dumps 181to minimize the number of tapes follows: 182.Bl -bullet -offset indent 183.It 184Always start with a level 0 backup, for example: 185.Bd -literal -offset indent 186/etc/dump 0ufds /dev/nrst1 54000 6000 /usr/src 187.Ed 188.Pp 189This should be done at set intervals, say once a month or once every two months, 190and on a set of fresh tapes that is saved forever. 191.It 192After a level 0, dumps of active file 193systems are taken on a daily basis, 194using a modified Tower of Hanoi algorithm, 195with this sequence of dump levels: 196.Bd -literal -offset indent 1973 2 5 4 7 6 9 8 9 9 ... 198.Ed 199.Pp 200For the daily dumps, it should be possible to use a fixed number of tapes 201for each day, used on a weekly basis. 202Each week, a level 1 dump is taken, and 203the daily Hanoi sequence repeats beginning with 3. 204For weekly dumps, another fixed set of tapes per dumped file system is 205used, also on a cyclical basis. 206.El 207.Pp 208After several months or so, the daily and weekly tapes should get 209rotated out of the dump cycle and fresh tapes brought in. 210.Sh FILES 211.Bl -tag -width /etc/dumpdates -compact 212.It Pa /dev/rrp1g 213default filesystem to dump from (system dependent). 214.It Pa /dev/rmt8 215default tape unit to dump to 216.It Pa /etc/dumpdates 217new format dump date record 218.It Pa /etc/fstab 219dump table: file systems and frequency 220.It Pa /etc/group 221to find group 222.Em operator 223.El 224.Sh SEE ALSO 225.Xr rdump 8 , 226.Xr restore 8 , 227.Xr dump 5 , 228.Xr fstab 5 229.Sh DIAGNOSTICS 230Many, and verbose. 231.Pp 232Dump exits with zero status on success. 233Startup errors are indicated with an exit code of 1; 234abnormal termination is indicated with an exit code of 3. 235.Sh BUGS 236.Pp 237Fewer than 32 read errors on the filesystem are ignored. 238Each reel requires a new process, so parent processes for 239reels already written just hang around until the entire tape 240is written. 241.Pp 242.Nm Dump 243with the 244.Cm W 245or 246.Cm w 247options does not report filesystems that have never been recorded 248in 249.Pa /etc/dumpdates , 250even if listed in 251.Pa /etc/fstab . 252.Pp 253It would be nice if 254.Nm dump 255knew about the dump sequence, 256kept track of the tapes scribbled on, 257told the operator which tape to mount when, 258and provided more assistance 259for the operator running 260.Xr restore . 261.Sh HISTORY 262A 263.Nm 264command appeared in Version 6 AT&T UNIX. 265