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 acknowledgment: 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.\" $FreeBSD: src/sbin/dump/dump.8,v 1.27.2.18 2003/02/23 19:58:23 trhodes Exp $ 35.\" 36.Dd March 1, 2002 37.Dt DUMP 8 38.Os 39.Sh NAME 40.Nm dump , 41.Nm rdump 42.Nd UFS file system backup 43.Sh SYNOPSIS 44.Nm 45.Op Fl 0123456789acknSu 46.Op Fl B Ar records 47.Op Fl b Ar blocksize 48.Op Fl D Ar dumpdates 49.Op Fl C Ar cachesize 50.Op Fl d Ar density 51.Op Fl f Ar file 52.Op Fl h Ar level 53.Op Fl s Ar feet 54.Op Fl T Ar date 55.Ar filesystem 56.Nm 57.Fl W | Fl w 58.Sh DESCRIPTION 59The 60.Nm 61utility examines files 62on a file system 63and determines which files 64need to be backed up. 65These files 66are copied to the given disk, tape or other 67storage medium for safe keeping (see the 68.Fl f 69option below for doing remote backups). 70A dump that is larger than the output medium is broken into 71multiple volumes. 72On most media the size is determined by writing until an 73end-of-media indication is returned. 74This 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 83.Fl B 84options. 85By default, the same output file name is used for each volume 86after prompting the operator to change media. 87.Pp 88The file system to be dumped is specified by the argument 89.Ar filesystem 90as either its device-special file or its mount point 91(if that is in a standard entry in 92.Pa /etc/fstab ) . 93.Pp 94.Nm 95may also be invoked as 96.Nm rdump . 97The 98.Bx 4.3 99option syntax is implemented for backward compatibility, but 100is not documented here. 101.Pp 102The following options are supported by 103.Nm : 104.Bl -tag -width Ds 105.It Fl 0-9 106Dump levels. 107A level 0, full backup, 108guarantees the entire file system is copied 109(but see also the 110.Fl h 111option below). 112A level number above 0, 113incremental backup, 114tells dump to 115copy all files new or modified since the 116last dump of any lower level. 117The default level is 0. 118.It Fl a 119.Dq auto-size . 120Bypass all tape length considerations, and enforce writing 121until an end-of-media indication is returned. 122This fits best for most modern tape drives. 123Use of this option is particularly 124recommended when appending to an existing tape, or using a tape 125drive with hardware compression (where you can never be sure about 126the compression ratio). 127.It Fl B Ar records 128The number of kilobytes per output volume, except that if it is 129not an integer multiple of the output block size, 130the command uses the next smaller such multiple. 131This option overrides the calculation of tape size 132based on length and density. 133.It Fl b Ar blocksize 134The number of kilobytes per output block, except that if it is 135larger than 64, the command uses 64. (See the BUGS section.) 136The default block size is 10. 137.It Fl c 138Change the defaults for use with a cartridge tape drive, with a density 139of 8000 bpi, and a length of 1700 feet. 140.It Fl D Ar dumpdates 141Specify an alternate path to the 142.Pa dumpdates 143file. 144The default is 145.Pa /etc/dumpdates . 146.It Fl C Ar cachesize 147Specify the cache size in megabytes. This will greatly improve performance 148at the cost of 149.Nm 150possibly not noticing changes in the filesystem between passes. 151Beware that 152.Nm 153forks, and the actual memory use may be larger than the specified cache 154size. The recommended cache size is between 8 and 32 (megabytes). 155.It Fl d Ar density 156Set tape density to 157.Ar density . 158The default is 1600BPI. 159.It Fl f Ar file 160Write the backup to 161.Ar file ; 162.Ar file 163may be a special device file 164like 165.Pa /dev/sa0 166(a tape drive), 167.Pa /dev/fd1 168(a floppy disk drive), 169an ordinary file, 170or 171.Sq Fl 172(the standard output). 173Multiple file names may be given as a single argument separated by commas. 174Each file will be used for one dump volume in the order listed; 175if the dump requires more volumes than the number of names given, 176the last file name will used for all remaining volumes after prompting 177for media changes. 178If the name of the file is of the form 179.Dq host:file , 180or 181.Dq user@host:file , 182.Nm 183writes to the named file on the remote host using 184.Xr rmt 8 . 185The default path name of the remote 186.Xr rmt 8 187program is 188.\" rmt path, is the path on the remote host 189.Pa /etc/rmt ; 190this can be overridden by the environment variable 191.Ev RMT . 192.It Fl h Ar level 193Honor the user 194.Dq nodump 195flag 196.Pq Dv UF_NODUMP 197only for dumps at or above the given 198.Ar level . 199The default honor level is 1, 200so that incremental backups omit such files 201but full backups retain them. 202.It Fl k 203Use Kerberos authentication to talk to remote tape servers. (Only 204available if this option was enabled when 205.Nm 206was compiled.) 207.It Fl n 208Whenever 209.Nm 210requires operator attention, 211notify all operators in the group 212.Dq operator 213by means similar to a 214.Xr wall 1 . 215.It Fl s Ar feet 216Attempt to calculate the amount of tape needed 217at a particular density. 218If this amount is exceeded, 219.Nm 220prompts for a new tape. 221It is recommended to be a bit conservative on this option. 222The default tape length is 2300 feet. 223.It Fl S 224Display an estimate of the backup size and the number of 225tapes required, and exit without actually performing the dump. 226.It Fl T Ar date 227Use the specified date as the starting time for the dump 228instead of the time determined from looking in 229the 230.Pa dumpdates 231file. 232The format of date is the same as that of 233.Xr ctime 3 . 234This option is useful for automated dump scripts that wish to 235dump over a specific period of time. 236The 237.Fl T 238option is mutually exclusive from the 239.Fl u 240option. 241.It Fl u 242Update the 243.Pa dumpdates 244file 245after a successful dump. 246The format of 247the 248.Pa dumpdates 249file 250is readable by people, consisting of one 251free format record per line: 252file system name, 253increment level 254and 255.Xr ctime 3 256format dump date. 257There may be only one entry per file system at each level. 258The 259.Pa dumpdates 260file 261may be edited to change any of the fields, 262if necessary. 263The default path for the 264.Pa dumpdates 265file is 266.Pa /etc/dumpdates , 267but the 268.Fl D 269option may be used to change it. 270.It Fl W 271Tell the operator what file systems need to be dumped. 272This information is gleaned from the files 273.Pa dumpdates 274and 275.Pa /etc/fstab . 276The 277.Fl W 278option causes 279.Nm 280to print out, for each file system in 281the 282.Pa dumpdates 283file 284the most recent dump date and level, 285and highlights those file systems that should be dumped. 286If the 287.Fl W 288option is set, all other options are ignored, and 289.Nm 290exits immediately. 291.It Fl w 292Is like 293.Fl W , 294but prints only those file systems which need to be dumped. 295.El 296.Pp 297Directories and regular files which have their 298.Dq nodump 299flag 300.Pq Dv UF_NODUMP 301set will be omitted along with everything under such directories, 302subject to the 303.Fl h 304option. 305.Pp 306The 307.Nm 308utility requires operator intervention on these conditions: 309end of tape, 310end of dump, 311tape write error, 312tape open error or 313disk read error (if there are more than a threshold of 32). 314In addition to alerting all operators implied by the 315.Fl n 316key, 317.Nm 318interacts with the operator on 319.Em dump's 320control terminal at times when 321.Nm 322can no longer proceed, 323or if something is grossly wrong. 324All questions 325.Nm 326poses 327.Em must 328be answered by typing 329.Dq yes 330or 331.Dq no , 332appropriately. 333.Pp 334Since making a dump involves a lot of time and effort for full dumps, 335.Nm 336checkpoints itself at the start of each tape volume. 337If writing that volume fails for some reason, 338.Nm 339will, 340with operator permission, 341restart itself from the checkpoint 342after the old tape has been rewound and removed, 343and a new tape has been mounted. 344.Pp 345The 346.Nm 347utility tells the operator what is going on at periodic intervals 348(every 5 minutes, or promptly after receiving 349.Dv SIGINFO ) , 350including usually low estimates of the number of blocks to write, 351the number of tapes it will take, the time to completion, and 352the time to the tape change. 353The output is verbose, 354so that others know that the terminal 355controlling 356.Nm 357is busy, 358and will be for some time. 359.Pp 360In the event of a catastrophic disk event, the time required 361to restore all the necessary backup tapes or files to disk 362can be kept to a minimum by staggering the incremental dumps. 363An efficient method of staggering incremental dumps 364to minimize the number of tapes follows: 365.Bl -bullet -offset indent 366.It 367Always start with a level 0 backup, for example: 368.Bd -literal -offset indent 369/sbin/dump -0u -f /dev/nsa0 /usr/src 370.Ed 371.Pp 372This should be done at set intervals, say once a month or once every two months, 373and on a set of fresh tapes that is saved forever. 374.It 375After a level 0, dumps of active file systems are taken on a daily basis, 376using a modified Tower of Hanoi algorithm, 377with this sequence of dump levels: 378.Bd -literal -offset indent 3793 2 5 4 7 6 9 8 9 9 ... 380.Ed 381.Pp 382For the daily dumps, it should be possible to use a fixed number of tapes 383for each day, used on a weekly basis. 384Each week, a level 1 dump is taken, and 385the daily Hanoi sequence repeats beginning with 3. 386For weekly dumps, another fixed set of tapes per dumped file system is 387used, also on a cyclical basis. 388.El 389.Pp 390After several months or so, the daily and weekly tapes should get 391rotated out of the dump cycle and fresh tapes brought in. 392.Sh ENVIRONMENT 393.Bl -tag -width ".Ev TAPE" 394.It Ev TAPE 395Device from which to read backup. 396.It Ev RMT 397Pathname of the remote 398.Xr rmt 8 399program. 400.El 401.Sh FILES 402.Bl -tag -width /etc/dumpdates -compact 403.It Pa /dev/sa0 404default tape unit to dump to 405.It Pa /etc/dumpdates 406dump date records 407(this can be changed; 408see the 409.Fl D 410option) 411.It Pa /etc/fstab 412dump table: file systems and frequency 413.It Pa /etc/group 414to find group 415.Em operator 416.El 417.Sh EXIT STATUS 418Dump exits with zero status on success. 419Startup errors are indicated with an exit code of 1; 420abnormal termination is indicated with an exit code of 3. 421.Sh DIAGNOSTICS 422Many, and verbose. 423.Sh SEE ALSO 424.Xr chflags 1 , 425.Xr fstab 5 , 426.Xr UFS 5 , 427.Xr restore 8 , 428.Xr rmt 8 429.Sh HISTORY 430A 431.Nm 432utility appeared in 433.At v6 . 434.Sh BUGS 435Fewer than 32 read errors on the file system are ignored. 436.Pp 437Each reel requires a new process, so parent processes for 438reels already written just hang around until the entire tape 439is written. 440.Pp 441Currently, 442.Xr physio 9 443slices all requests into chunks of 64 KB. 444Therefore, it is 445impossible to use a larger output block size, so 446.Nm 447will prevent this from happening. 448.Pp 449The 450.Nm 451utility with the 452.Fl W 453or 454.Fl w 455options does not report file systems that have never been recorded 456in the 457.Pa dumpdates 458file, 459even if listed in 460.Pa /etc/fstab . 461.Pp 462It would be nice if 463.Nm 464knew about the dump sequence, 465kept track of the tapes scribbled on, 466told the operator which tape to mount when, 467and provided more assistance 468for the operator running 469.Xr restore 8 . 470.Pp 471The 472.Nm 473utility cannot do remote backups without being run as root, due to its 474security history. 475This may be fixed in a later version of 476.Dx . 477Presently, it works if you set it setuid (like it used to be), but this 478might constitute a security risk. 479