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 6.11 (Berkeley) 01/25/93 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 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 , 74or 75.Dq user@host:file , 76.Nm dump 77writes to the named file on the remote host using 78.Xr rmt 8 . 79.It Cm d Ar density 80Set tape density to 81.Ar density . 82The default is 1600BPI. 83.It Cm n 84Whenever 85.Nm dump 86requires operator attention, 87notify all operators in the group 88.Dq operator 89by means similar to a 90.Xr wall 1 . 91.It Cm s Ar feet 92Attempt to calculate the amount of tape needed 93at a particular density. 94If this amount is exceeded, 95.Nm dump 96prompts for a new tape. 97It is recommended to be a bit conservative on this option. 98The default tape length is 2300 feet. 99.It Cm u 100Update the file 101.Pa /etc/dumpdates 102after a successful dump. 103The format of 104.Pa /etc/dumpdates 105is readable by people, consisting of one 106free format record per line: 107filesystem name, 108increment level 109and 110.Xr ctime 3 111format dump date. 112There may be only one entry per filesystem at each level. 113The file 114.Pa /etc/dumpdates 115may be edited to change any of the fields, 116if necessary. 117.It Cm T Ar date 118Use the specified date as the starting time for the dump 119instead of the time determined from looking in 120.Pa /etc/dumpdates . 121The format of date is the same as that of 122.Xr ctime 3 . 123This option is useful for automated dump scripts that wish to 124dump over a specific period of time. 125The 126.Cm T 127option is mutually exclusive from the 128.Cm u 129option. 130.It Cm W 131.Nm Dump 132tells the operator what file systems need to be dumped. 133This information is gleaned from the files 134.Pa /etc/dumpdates 135and 136.Pa /etc/fstab . 137The 138.Cm W 139option causes 140.Nm dump 141to print out, for each file system in 142.Pa /etc/dumpdates 143the most recent dump date and level, 144and highlights those file systems that should be dumped. 145If the 146.Cm W 147option is set, all other options are ignored, and 148.Nm dump 149exits immediately. 150.It Cm w 151Is like W, but prints only those filesystems which need to be dumped. 152.El 153.Pp 154.Nm Dump 155requires operator intervention on these conditions: 156end of tape, 157end of dump, 158tape write error, 159tape open error or 160disk read error (if there are more than a threshold of 32). 161In addition to alerting all operators implied by the 162.Cm n 163key, 164.Nm dump 165interacts with the operator on 166.Em dump's 167control terminal at times when 168.Nm dump 169can no longer proceed, 170or if something is grossly wrong. 171All questions 172.Nm dump 173poses 174.Em must 175be answered by typing 176.Dq yes 177or 178.Dq no , 179appropriately. 180.Pp 181Since making a dump involves a lot of time and effort for full dumps, 182.Nm dump 183checkpoints itself at the start of each tape volume. 184If writing that volume fails for some reason, 185.Nm dump 186will, 187with operator permission, 188restart itself from the checkpoint 189after the old tape has been rewound and removed, 190and a new tape has been mounted. 191.Pp 192.Nm Dump 193tells the operator what is going on at periodic intervals, 194including usually low estimates of the number of blocks to write, 195the number of tapes it will take, the time to completion, and 196the time to the tape change. 197The output is verbose, 198so that others know that the terminal 199controlling 200.Nm dump 201is busy, 202and will be for some time. 203.Pp 204In the event of a catastrophic disk event, the time required 205to restore all the necessary backup tapes or files to disk 206can be kept to a minimum by staggering the incremental dumps. 207An efficient method of staggering incremental dumps 208to minimize the number of tapes follows: 209.Bl -bullet -offset indent 210.It 211Always start with a level 0 backup, for example: 212.Bd -literal -offset indent 213/etc/dump 0uf /dev/nrst1 /usr/src 214.Ed 215.Pp 216This should be done at set intervals, say once a month or once every two months, 217and on a set of fresh tapes that is saved forever. 218.It 219After a level 0, dumps of active file 220systems are taken on a daily basis, 221using a modified Tower of Hanoi algorithm, 222with this sequence of dump levels: 223.Bd -literal -offset indent 2243 2 5 4 7 6 9 8 9 9 ... 225.Ed 226.Pp 227For the daily dumps, it should be possible to use a fixed number of tapes 228for each day, used on a weekly basis. 229Each week, a level 1 dump is taken, and 230the daily Hanoi sequence repeats beginning with 3. 231For weekly dumps, another fixed set of tapes per dumped file system is 232used, also on a cyclical basis. 233.El 234.Pp 235After several months or so, the daily and weekly tapes should get 236rotated out of the dump cycle and fresh tapes brought in. 237.Sh FILES 238.Bl -tag -width /etc/dumpdates -compact 239.It Pa /dev/rmt8 240default tape unit to dump to 241.It Pa /etc/dumpdates 242dump date records 243.It Pa /etc/fstab 244dump table: file systems and frequency 245.It Pa /etc/group 246to find group 247.Em operator 248.El 249.Sh SEE ALSO 250.Xr restore 8 , 251.Xr rmt 8 , 252.Xr dump 5 , 253.Xr fstab 5 254.Sh DIAGNOSTICS 255Many, and verbose. 256.Pp 257Dump exits with zero status on success. 258Startup errors are indicated with an exit code of 1; 259abnormal termination is indicated with an exit code of 3. 260.Sh BUGS 261.Pp 262Fewer than 32 read errors on the filesystem are ignored. 263Each reel requires a new process, so parent processes for 264reels already written just hang around until the entire tape 265is written. 266.Pp 267.Nm Dump 268with the 269.Cm W 270or 271.Cm w 272options does not report filesystems that have never been recorded 273in 274.Pa /etc/dumpdates , 275even if listed in 276.Pa /etc/fstab . 277.Pp 278It would be nice if 279.Nm dump 280knew about the dump sequence, 281kept track of the tapes scribbled on, 282told the operator which tape to mount when, 283and provided more assistance 284for the operator running 285.Xr restore . 286.Sh HISTORY 287A 288.Nm dump 289command appeared in Version 6 AT&T UNIX. 290