DUMP(8) BSD System Manager's Manual DUMP(8)
NAME
dump -- ext2 filesystem backup
SYNOPSIS
dump [-0123456789ackMnqSu] [-A file] [-B records] [-b blocksize] [-d density] [-e inode numbers] [-E file] [-f file] [-F script] [-h level]
[-I nr errors] [-j compression level] [-L label] [-Q file] [-s feet] [-T date] [-z compression level] files-to-dump
dump [-W | -w]
(The 4.3BSD option syntax is implemented for backward compatibility but is not documented here.)
DESCRIPTION
Dump examines files on an ext2 filesystem and determines which files need to be backed up. These files are copied to the given disk, tape or
other storage medium for safe keeping (see the -f option below for doing remote backups). A dump that is larger than the output medium is
broken into multiple volumes. On most media the size is determined by writing until an end-of-media indication is returned.
On media that cannot reliably return an end-of-media indication (such as some cartridge tape drives), each volume is of a fixed size; the
actual size is determined by specifying cartridge media, or via the tape size, density and/or block count options below. By default, the
same output file name is used for each volume after prompting the operator to change media.
files-to-dump is either a mountpoint of a filesystem or a list of files and directories to be backed up as a subset of a filesystem. In the
former case, either the path to a mounted filesystem or the device of an unmounted filesystem can be used. In the latter case, certain
restrictions are placed on the backup: -u is not allowed, the only dump level that is supported is -0 and all the files and directories must
reside on the same filesystem.
The following options are supported by dump:
-0-9 Dump levels. A level 0, full backup, guarantees the entire file system is copied (but see also the -h option below). A level number
above 0, incremental backup, tells dump to copy all files new or modified since the last dump of a lower level. The default level is
9.
-a ``auto-size''. Bypass all tape length calculations, and write until an end-of-media indication is returned. This works best for
most modern tape drives, and is the default. Use of this option is particularly recommended when appending to an existing tape, or
using a tape drive with hardware compression (where you can never be sure about the compression ratio).
-A archive_file
Archive a dump table-of-contents in the specified archive_file to be used by restore(8) to determine whether a file is in the dump
file that is being restored.
-b blocksize
The number of kilobytes per dump record. Since the IO system slices all requests into chunks of MAXBSIZE (typically 64kB), it is not
possible to use a larger blocksize without having problems later with restore(8). Therefore dump will constrain writes to MAXBSIZE.
The default blocksize is 10.
-B records
The number of 1 kB blocks per volume. Not normally required, as dump can detect end-of-media. When the specified size is reached,
dump waits for you to change the volume. This option overrides the calculation of tape size based on length and density. If com-
pression is on this limits the size of the compressed output per volume.
-c Change the defaults for use with a cartridge tape drive, with a density of 8000 bpi, and a length of 1700 feet. Specifying a car-
tridge drive overrides the end-of-media detection.
-d density
Set tape density to density. The default is 1600BPI. Specifying a tape density overrides the end-of-media detection.
-e inodes
Exclude inodes from the dump. The inodes parameter is a comma separated list of inode numbers (you can use stat to find the inode
number for a file or directory).
-E file
Read list of inodes to be excluded from the dump from the text file file. The file file should be an ordinary file containing inode
numbers separated by newlines.
-f file
Write the backup to file; file may be a special device file like /dev/st0 (a tape drive), /dev/rsd1c (a floppy disk drive), an ordi-
nary file, or '-' (the standard output). Multiple file names may be given as a single argument separated by commas. Each file will
be used for one dump volume in the order listed; if the dump requires more volumes than the number of names given, the last file name
will used for all remaining volumes after prompting for media changes. If the name of the file is of the form ``host:file'' or
``user@host:file'' dump writes to the named file on the remote host using rmt(8). The default path name of the remote rmt(8) program
is /etc/rmt; this can be overridden by the environment variable RMT.
-F script
Run script at the end of each tape. The device name and the current volume number are passed on the command line. The script must
return 0 if dump should continue without asking the user to change the tape, 1 if dump should continue but ask the user to change the
tape. Any other exit code will cause dump to abort. For security reasons, dump reverts back to the real user ID and the real group
ID before running the script.
-h level
Honor the user ``nodump'' flag only for dumps at or above the given level. The default honor level is 1, so that incremental backups
omit such files but full backups retain them.
-I nr errors
By default, dump will ignore the first 32 read errors on the file system before asking for operator intervention. You can change this
using this flag to any value. This is useful when running dump on an active filesystem where read errors simply indicate an inconsis-
tency between the mapping and dumping passes.
-j compression level
Compress every block to be written on the tape using bzlib library. This option will work only when dumping to a file or pipe or,
when dumping to a tape drive, if the tape drive is capable of writing variable length blocks. You will need at least the 0.4b24 ver-
sion of restore in order to extract compressed tapes. Tapes written using compression will not be compatible with the BSD tape for-
mat. The (optional) parameter specifies the compression level bzlib will use. The default compression level is 2. If the optional
parameter is specified, there should be no white space between the option letter and the parameter.
-k Use Kerberos authentication to talk to remote tape servers. (Only available if this option was enabled when dump was compiled.)
-L label
The user-supplied text string label is placed into the dump header, where tools like restore(8) and file(1) can access it. Note that
this label is limited to be at most LBLSIZE (currently 16) characters, which must include the terminating '