1.\" Copyright (c) 1980, 1991, 1993 2.\" Regents of the University of California. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 15.\" This product includes software developed by the University of 16.\" California, Berkeley and its contributors. 17.\" 4. Neither the name of the University nor the names of its contributors 18.\" may be used to endorse or promote products derived from this software 19.\" without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" @(#)dump.8 8.3 (Berkeley) 5/1/95 34.\" $Id: dump.8,v 1.13 1997/03/11 12:09:31 peter Exp $ 35.\" 36.Dd May 1, 1995 37.Dt DUMP 8 38.Os BSD 4 39.Sh NAME 40.Nm dump 41.Nd filesystem backup 42.Sh SYNOPSIS 43.Nm dump 44.Op Fl 0123456789acnu 45.Op Fl B Ar records 46.Op Fl b Ar blocksize 47.Op Fl d Ar density 48.Op Fl f Ar file 49.Op Fl h Ar level 50.Op Fl s Ar feet 51.Op Fl T Ar date 52.Ar filesystem 53.Nm dump 54.Op Fl W Li \&| Fl w 55.Pp 56.in -\\n(iSu 57(The 58.Bx 4.3 59option syntax is implemented for backward compatibility, but 60is not documented here.) 61.Sh DESCRIPTION 62.Nm Dump 63examines files 64on a filesystem 65and determines which files 66need to be backed up. These files 67are copied to the given disk, tape or other 68storage medium for safe keeping (see the 69.Fl f 70option below for doing remote backups). 71A dump that is larger than the output medium is broken into 72multiple volumes. 73On most media the size is determined by writing until an 74end-of-media indication is returned. This can be enforced 75by using the 76.Fl a 77option. 78.Pp 79On media that cannot reliably return an end-of-media indication 80(such as some cartridge tape drives) 81each volume is of a fixed size; 82the actual size is determined by the tape size and density and/or 83block count options below. 84By default, the same output file name is used for each volume 85after prompting the operator to change media. 86.Pp 87The following options are supported by 88.Nm dump : 89.Bl -tag -width Ds 90.It Fl 0\-9 91Dump levels. 92A level 0, full backup, 93guarantees the entire file system is copied 94(but see also the 95.Fl h 96option below). 97A level number above 0, 98incremental backup, 99tells dump to 100copy all files new or modified since the 101last dump of the same or lower level. 102The default level is 9. 103.It Fl B Ar records 104The number of dump records per volume. 105This option overrides the calculation of tape size 106based on length and density. 107.It Fl a 108.Dq auto-size . 109Bypass all tape length considerations, and enforce writing 110until an end-of-media indication is returned. This fits best 111for most modern tape drives. Use of this option is particularly 112recommended when appending to an existing tape, or using a tape 113drive with hardware compression (where you can never be sure about 114the compression ratio). 115.It Fl b Ar blocksize 116The number of kilobytes per dump record. 117.It Fl c 118Change the defaults for use with a cartridge tape drive, with a density 119of 8000 bpi, and a length of 1700 feet. 120.It Fl h Ar level 121Honor the user 122.Dq nodump 123flag 124.Dp Dv UF_NODUMP 125only for dumps at or above the given 126.Ar level . 127The default honor level is 1, 128so that incremental backups omit such files 129but full backups retain them. 130.It Fl d Ar density 131Set tape density to 132.Ar density . 133The default is 1600BPI. 134.It Fl f Ar file 135Write the backup to 136.Ar file ; 137.Ar file 138may be a special device file 139like 140.Pa /dev/rst0 141(a tape drive), 142.Pa /dev/rfd1 143(a floppy disk drive), 144an ordinary file, 145or 146.Ql Fl 147(the standard output). 148Multiple file names may be given as a single argument separated by commas. 149Each file will be used for one dump volume in the order listed; 150if the dump requires more volumes than the number of names given, 151the last file name will used for all remaining volumes after prompting 152for media changes. 153If the name of the file is of the form 154.Dq host:file , 155or 156.Dq user@host:file , 157.Nm dump 158writes to the named file on the remote host using 159.Xr rmt 8 . 160The default path name of the remote 161.Xr rmt 8 162program is 163.\" rmt path, is the path on the remote host 164.Pa /etc/rmt ; 165this can be overridden by the environment variable 166.Ev RMT . 167.It Fl n 168Whenever 169.Nm dump 170requires operator attention, 171notify all operators in the group 172.Dq operator 173by means similar to a 174.Xr wall 1 . 175.It Fl s Ar feet 176Attempt to calculate the amount of tape needed 177at a particular density. 178If this amount is exceeded, 179.Nm dump 180prompts for a new tape. 181It is recommended to be a bit conservative on this option. 182The default tape length is 2300 feet. 183.ne 1i 184.It Fl T Ar date 185Use the specified date as the starting time for the dump 186instead of the time determined from looking in 187.Pa /etc/dumpdates . 188The format of date is the same as that of 189.Xr ctime 3 . 190This option is useful for automated dump scripts that wish to 191dump over a specific period of time. 192The 193.Fl T 194option is mutually exclusive from the 195.Fl u 196option. 197.It Fl u 198Update the file 199.Pa /etc/dumpdates 200after a successful dump. 201The format of 202.Pa /etc/dumpdates 203is readable by people, consisting of one 204free format record per line: 205filesystem name, 206increment level 207and 208.Xr ctime 3 209format dump date. 210There may be only one entry per filesystem at each level. 211The file 212.Pa /etc/dumpdates 213may be edited to change any of the fields, 214if necessary. 215.It Fl W 216.Nm Dump 217tells the operator what file systems need to be dumped. 218This information is gleaned from the files 219.Pa /etc/dumpdates 220and 221.Pa /etc/fstab . 222The 223.Fl W 224option causes 225.Nm dump 226to print out, for each file system in 227.Pa /etc/dumpdates 228the most recent dump date and level, 229and highlights those file systems that should be dumped. 230If the 231.Fl W 232option is set, all other options are ignored, and 233.Nm dump 234exits immediately. 235.It Fl w 236Is like W, but prints only those filesystems which need to be dumped. 237.El 238.Pp 239.Nm Dump 240requires operator intervention on these conditions: 241end of tape, 242end of dump, 243tape write error, 244tape open error or 245disk read error (if there are more than a threshold of 32). 246In addition to alerting all operators implied by the 247.Fl n 248key, 249.Nm dump 250interacts with the operator on 251.Em dump's 252control terminal at times when 253.Nm dump 254can no longer proceed, 255or if something is grossly wrong. 256All questions 257.Nm dump 258poses 259.Em must 260be answered by typing 261.Dq yes 262or 263.Dq no , 264appropriately. 265.Pp 266Since making a dump involves a lot of time and effort for full dumps, 267.Nm dump 268checkpoints itself at the start of each tape volume. 269If writing that volume fails for some reason, 270.Nm dump 271will, 272with operator permission, 273restart itself from the checkpoint 274after the old tape has been rewound and removed, 275and a new tape has been mounted. 276.Pp 277.Nm Dump 278tells the operator what is going on at periodic intervals, 279including usually low estimates of the number of blocks to write, 280the number of tapes it will take, the time to completion, and 281the time to the tape change. 282The output is verbose, 283so that others know that the terminal 284controlling 285.Nm dump 286is busy, 287and will be for some time. 288.Pp 289In the event of a catastrophic disk event, the time required 290to restore all the necessary backup tapes or files to disk 291can be kept to a minimum by staggering the incremental dumps. 292An efficient method of staggering incremental dumps 293to minimize the number of tapes follows: 294.Bl -bullet -offset indent 295.It 296Always start with a level 0 backup, for example: 297.Bd -literal -offset indent 298/sbin/dump -0u -f /dev/nrst0 /usr/src 299.Ed 300.Pp 301This should be done at set intervals, say once a month or once every two months, 302and on a set of fresh tapes that is saved forever. 303.It 304After a level 0, dumps of active file 305systems are taken on a daily basis, 306using a modified Tower of Hanoi algorithm, 307with this sequence of dump levels: 308.Bd -literal -offset indent 3093 2 5 4 7 6 9 8 9 9 ... 310.Ed 311.Pp 312For the daily dumps, it should be possible to use a fixed number of tapes 313for each day, used on a weekly basis. 314Each week, a level 1 dump is taken, and 315the daily Hanoi sequence repeats beginning with 3. 316For weekly dumps, another fixed set of tapes per dumped file system is 317used, also on a cyclical basis. 318.El 319.Pp 320After several months or so, the daily and weekly tapes should get 321rotated out of the dump cycle and fresh tapes brought in. 322.Sh ENVIRONMENT 323The environment variable 324.Ev RMT 325will be used to determine the pathname of the remote 326.Xr rmt 8 327program. 328.Sh FILES 329.Bl -tag -width /etc/dumpdates -compact 330.It Pa /dev/rst0 331default tape unit to dump to 332.It Pa /etc/dumpdates 333dump date records 334.It Pa /etc/fstab 335dump table: file systems and frequency 336.It Pa /etc/group 337to find group 338.Em operator 339.El 340.Sh SEE ALSO 341.Xr dump 5 , 342.Xr fstab 5 , 343.Xr ft 8 , 344.Xr restore 8 , 345.Xr rmt 8 346.Sh DIAGNOSTICS 347Many, and verbose. 348.Pp 349Dump exits with zero status on success. 350Startup errors are indicated with an exit code of 1; 351abnormal termination is indicated with an exit code of 3. 352.Sh BUGS 353Fewer than 32 read errors on the filesystem are ignored. 354.Pp 355Each reel requires a new process, so parent processes for 356reels already written just hang around until the entire tape 357is written. 358.Pp 359Currently, 360.Xr physio 9 361slices all requests into chunks of 64 KB. Therefore, it is 362impossible to use a larger tape blocksize, so 363.Nm dump 364will prevent this from happening. 365.Pp 366.Nm Dump 367with the 368.Fl W 369or 370.Fl w 371options does not report filesystems that have never been recorded 372in 373.Pa /etc/dumpdates , 374even if listed in 375.Pa /etc/fstab . 376.Pp 377It would be nice if 378.Nm dump 379knew about the dump sequence, 380kept track of the tapes scribbled on, 381told the operator which tape to mount when, 382and provided more assistance 383for the operator running 384.Xr restore . 385.Pp 386.Nm dump 387cannot do remote backups without being run as root, due to its 388security history. This will be fixed in a later version of FreeBSD. 389Presently, it work if you set it setuid (like it used to be), but this 390might constitute a security risk. 391.Sh HISTORY 392A 393.Nm dump 394command appeared in 395.At v6 . 396