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 6.10 (Berkeley) 06/20/92 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 0123456789fusTdWn 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. 47A level number above 0, 48incremental backup, 49tells dump to 50copy all files new or modified since the 51last dump of the same or lower level. The default 52level is 9. 53.It Cm f Op Ar file 54Write the backup to 55.Ar file ; 56.Ar file 57may be a special device file 58like 59.Pa /dev/rmt12 60(a tape drive), 61.Pa /dev/rsd1c 62(a disk drive), 63an ordinary file, 64or 65.Ql Fl 66(the standard output). 67Multiple file names may be given as a single argument separated by commas. 68Each file will be used for one dump volume in the order listed; 69if the dump requires more volumes than the number of names given, 70the last file name will used for all remaining volumes after prompting 71for media changes. 72If the name of the file is of the form 73.Dq host:file , 74.Nm dump 75writes to the named file on the remote host using 76.Xr rmt 8 . 77.It Cm d Ar density 78Set tape density to 79.Ar density . 80The default is 1600BPI. 81.It Cm n 82Whenever 83.Nm dump 84requires operator attention, 85notify all operators in the group 86.Dq operator 87by means similar to a 88.Xr wall 1 . 89.It Cm s Ar feet 90Attempt to calculate the amount of tape needed 91at a particular density. 92If this amount is exceeded, 93.Nm dump 94prompts for a new tape. 95It is recommended to be a bit conservative on this option. 96The default tape length is 2300 feet. 97.It Cm u 98Update the file 99.Pa /etc/dumpdates 100after a successful dump. 101The format of 102.Pa /etc/dumpdates 103is readable by people, consisting of one 104free format record per line: 105filesystem name, 106increment level 107and 108.Xr ctime 3 109format dump date. 110There may be only one entry per filesystem at each level. 111The file 112.Pa /etc/dumpdates 113may be edited to change any of the fields, 114if necessary. 115.It Cm T Ar date 116Use the specified date as the starting time for the dump 117instead of the time determined from looking in 118.Pa /etc/dumpdates . 119The format of date is the same as that of 120.Xr ctime 3 . 121This option is useful for automated dump scripts that wish to 122dump over a specific period of time. 123The 124.Cm T 125option is mutually exclusive from the 126.Cm u 127option. 128.It Cm W 129.Nm Dump 130tells the operator what file systems need to be dumped. 131This information is gleaned from the files 132.Pa /etc/dumpdates 133and 134.Pa /etc/fstab . 135The 136.Cm W 137option causes 138.Nm dump 139to print out, for each file system in 140.Pa /etc/dumpdates 141the most recent dump date and level, 142and highlights those file systems that should be dumped. 143If the 144.Cm W 145option is set, all other options are ignored, and 146.Nm dump 147exits immediately. 148.It Cm w 149Is like W, but prints only those filesystems which need to be dumped. 150.El 151.Pp 152.Nm Dump 153requires operator intervention on these conditions: 154end of tape, 155end of dump, 156tape write error, 157tape open error or 158disk read error (if there are more than a threshold of 32). 159In addition to alerting all operators implied by the 160.Cm n 161key, 162.Nm dump 163interacts with the operator on 164.Em dump's 165control terminal at times when 166.Nm dump 167can no longer proceed, 168or if something is grossly wrong. 169All questions 170.Nm dump 171poses 172.Em must 173be answered by typing 174.Dq yes 175or 176.Dq no , 177appropriately. 178.Pp 179Since making a dump involves a lot of time and effort for full dumps, 180.Nm dump 181checkpoints itself at the start of each tape volume. 182If writing that volume fails for some reason, 183.Nm dump 184will, 185with operator permission, 186restart itself from the checkpoint 187after the old tape has been rewound and removed, 188and a new tape has been mounted. 189.Pp 190.Nm Dump 191tells the operator what is going on at periodic intervals, 192including usually low estimates of the number of blocks to write, 193the number of tapes it will take, the time to completion, and 194the time to the tape change. 195The output is verbose, 196so that others know that the terminal 197controlling 198.Nm dump 199is busy, 200and will be for some time. 201.Pp 202In the event of a catastrophic disk event, the time required 203to restore all the necessary backup tapes or files to disk 204can be kept to a minimum by staggering the incremental dumps. 205An efficient method of staggering incremental dumps 206to minimize the number of tapes follows: 207.Bl -bullet -offset indent 208.It 209Always start with a level 0 backup, for example: 210.Bd -literal -offset indent 211/etc/dump 0uf /dev/nrst1 /usr/src 212.Ed 213.Pp 214This should be done at set intervals, say once a month or once every two months, 215and on a set of fresh tapes that is saved forever. 216.It 217After a level 0, dumps of active file 218systems are taken on a daily basis, 219using a modified Tower of Hanoi algorithm, 220with this sequence of dump levels: 221.Bd -literal -offset indent 2223 2 5 4 7 6 9 8 9 9 ... 223.Ed 224.Pp 225For the daily dumps, it should be possible to use a fixed number of tapes 226for each day, used on a weekly basis. 227Each week, a level 1 dump is taken, and 228the daily Hanoi sequence repeats beginning with 3. 229For weekly dumps, another fixed set of tapes per dumped file system is 230used, also on a cyclical basis. 231.El 232.Pp 233After several months or so, the daily and weekly tapes should get 234rotated out of the dump cycle and fresh tapes brought in. 235.Sh FILES 236.Bl -tag -width /etc/dumpdates -compact 237.It Pa /dev/rmt8 238default tape unit to dump to 239.It Pa /etc/dumpdates 240dump date records 241.It Pa /etc/fstab 242dump table: file systems and frequency 243.It Pa /etc/group 244to find group 245.Em operator 246.El 247.Sh SEE ALSO 248.Xr restore 8 , 249.Xr rmt 8 , 250.Xr dump 5 , 251.Xr fstab 5 252.Sh DIAGNOSTICS 253Many, and verbose. 254.Pp 255Dump exits with zero status on success. 256Startup errors are indicated with an exit code of 1; 257abnormal termination is indicated with an exit code of 3. 258.Sh BUGS 259.Pp 260Fewer than 32 read errors on the filesystem are ignored. 261Each reel requires a new process, so parent processes for 262reels already written just hang around until the entire tape 263is written. 264.Pp 265.Nm Dump 266with the 267.Cm W 268or 269.Cm w 270options does not report filesystems that have never been recorded 271in 272.Pa /etc/dumpdates , 273even if listed in 274.Pa /etc/fstab . 275.Pp 276It would be nice if 277.Nm dump 278knew about the dump sequence, 279kept track of the tapes scribbled on, 280told the operator which tape to mount when, 281and provided more assistance 282for the operator running 283.Xr restore . 284.Sh HISTORY 285A 286.Nm dump 287command appeared in Version 6 AT&T UNIX. 288