dump(8)dump(8)Namedump - create file system dumpSyntax
/etc/dump [ key [ argument... ] filesystem ]
The command copies all files changed after a certain date from a speci‐
fied filesystem to a file, a pipe, magnetic tapes, or disks. The key
specifies the date and other options to be used by
Dumping a filesystem requires operator attention. An operator must
intervene when the end of a tape or disk is reached, when the end of
the occurs, or when an unrecoverable input disk read error occurs (if
more than 32 read errors occur). In addition to alerting all operators
in the operator group, interacts with the operator at the control ter‐
minal when can no longer proceed, or if something is grossly wrong.
All questions that poses must be answered by typing yes or no.
Because a full dump uses considerable system time, checkpoints itself
at the start of each tape or disk volume. If writing that volume
fails, asks the operator to restart from the checkpoint after the
present tape or disk has been replaced.
The utility reports to the operator periodically, giving usually low
estimates of the number of blocks to write, the number of tapes or
disks the dump will take, the time to completion, and the time until
the tape or disk must be changed. The output is verbose, so that oth‐
ers know that the terminal controlling is busy, and will be for some
This utility supports EOT handling which allows the use of multiple
media. The utility prompts for the next volume when it encounters the
end of the current volume.
This utility supports the TA90 style sequential stacker loader device.
The device ejects a cartridge wehn it is taken off line. The utility
performs the device ejection on behalf of the user when it encounters a
multivolume boundary during write or read operations involving tape.
The device then automatically loads the next available tape (if there
is one). The utility then attempts to access this next tape for a rea‐
sonable amount of time (approximately three minutes) before prompting
the user for a manual reload operation.
With the command, you specify a string of one or more of the options
described below. If no options are specified, the key 9u is assumed.
0-9 Specifies the dump level. All files that were modified since
the last date stored in the file for the same filesystem at
lesser levels will be dumped. If no date is determined by the
level, the beginning of time is assumed. Thus, the level 0
causes the entire filesystem to be dumped.
B Indicates that the next argument is a number that specifies the
size, in 1024-byte blocks, of a storage medium, such as a
diskette or removable disk cartridge. See the first example.
Additionally, permits the utility to kill subprocesses that
have finished writing. (This provides some relief to small
b Indicates that the next argument is the blocking factor for
tape records. The default is 10 and the maximum is 63. The
tape records are stored in 1024-byte blocks.
d Indicates that the density of the tape, expressed in bits per
inch, is taken from the next argument. This density is used in
calculating the amount of tape used per reel. The default den‐
sity is 1600 bpi.
f Places the dump on the file or device specified by the next
argument. If the name of the file is -, writes to standard
output. The default dump device is
Permits the program to treat the tape drive as a sequential loader
device even though it is not represented as such in the system
n Notifies, by means similar to a command, all users in the group
operator when needs operator attention.
S Prints output file size in bytes, or number of volumes for
devices. See the third example.
s Indicates that the next argument specifies the size of the dump
tape, in feet. When the specified size is reached, waits for
the reel to be changed. The default tape size is 2300 feet.
u Writes the date of the beginning of the dump on the file if the
completes successfully. This file records a separate date for
each filesystem and each dump level. The format of consists of
one free format record per line: filesystem name, increment
level and format dump date. The superuser can carefully edit
to change any of the fields.
W Tells the operator which file systems need to be dumped. This
information is taken from the files and The W option causes to
print out, for each file system in the most recent dump date
and level, and highlights those file systems that should be
dumped. If the W option is used, all other options are
ignored, and exits immediately.
w Lists only those filesystems that need to be dumped.
This example dumps the filesystem to RX50 diskettes. The option is
needed when running to read this dump.
dump 9Bf 400 /dev/rra2a /dev/ra0a
This example dumps the filesystem to a 6250 bpi tape on a TU78 tape
dump 0undf 6250 /dev/rmt?h /usr/users
This example reports number of bytes to be output for a level 0 dump of
the root file system. Please note: the file test is not created.
dump 0Sf test /
The program aborts with a segmentation fault if your file has been mis-
Estimated sizes for unuspported tape drives are based on 1600-bpi
Anything fewer than 32 read errors on the filesystem are ignored.
Each reel requires a new process, so child processes for reels already
written remain until the entire tape is written (unless the -B option
Using a blocking factor other than the default may lead to higher per‐
formance. However, you must select a value that is compatible with the
hardware limitations of the source and destination machines.
Default filesystem to dump from
Default tape unit to dump to
Dump date record
Dump table: file systems and frequency
Operator group definition
Required for user interface
See Alsodump(5), fstab(5), opser(8), restore(8), rrestore(8c)
Guide to Backup and Restore