DUMP(8) | System Manager's Manual | DUMP(8) |
dump
, rdump
—
dump |
[-0123456789aceFinStuX ]
[-B records]
[-b blocksize]
[-d density]
[-f file]
[-h level]
[-k read-blocksize]
[-L label]
[-l timeout]
[-r cachesize]
[-s feet]
[-T date]
[-U dumpdev]
[-x snap-backup]
files-to-dump |
dump |
[-W |
-w ]
(4.3BSD option syntax is implemented for backward compatibility, but not documented here.) |
dump
examines files on a file system 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. This can be enforced by using the -a
option.
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 the tape size and 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 single file
system, or a list of files and directories on a single file system to be
backed up as a subset of the file system. In the former case,
files-to-dump may be the device of a file system, the
path to a currently mounted file system, the path to an unmounted file
system listed in /etc/fstab, or, if
-F
is given, a file system image. In the latter
case, certain restrictions are placed on the backup:
-u
is ignored, the only dump level that is supported
is -0
, and all of the files must reside on the same
file system.
Any files with the superuser “log” flag
(SF_LOG
) set will be skipped. These files are
assumed to be wapbl(4) journal
files and will not be backed up.
The following options are supported by
dump
:
-0-9
-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 (but see also the
-i
option below). The default level is 9.-a
-B
records-b
blocksize-c
-d
density-e
-F
-f
file-
’ (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 be 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). Note that methods
more secure than rsh(1) (such
as ssh(1)) can be used to
invoke rmt(8) on the remote
host, via the environment variable RCMD_CMD
. See
rcmd(3) for more details.-h
levelUF_NODUMP
) 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
-k
read-blocksize-L
label\0
’.-l
timeoutdump
falls back to
the default behavior, and prompts the operator for the next tape.-n
dump
requires operator attention, notify
all operators in the group “operator” using
wall(1).-r
cachesize-k
option for the size of the
buffers. Maximum is 512, the size of the cache is limited to 15% of the
avail RAM by default.-S
-s
feetdump
prompts for a new
tape. It is recommended to be a bit conservative on this option. The
default tape length is 2300 feet.-T
date-T
option and the
-u
option are mutually exclusive.-t
dump
will have the time prepended to them. Also, the completion time interval
estimations will have the estimated time at which the dump will complete
printed at the end of the line.-u
-T
option is used or if a list of files or subdirectories is being dumped (as
opposed to an entire file system), then -u
is
ignored.-U
dumpdev-u
but specifies the device in
/etc/dumpdates as dumpdev.
This option can be used with subdir dumps and with the
-T
option.-W
dump
tells the operator what file systems need to
be dumped. This information is gleaned from the files
/etc/dumpdates and
/etc/fstab. The -W
option
causes dump
to print out, for each file system in
/etc/dumpdates the most recent dump date and
level, and highlights those file systems that should be dumped. If the
-W
option is set, all other options are ignored,
and dump
exits immediately.-w
-W
, but prints only those file systems which
need to be dumped.-X
-x
but uses a file system internal
snapshot on the file system to be dumped.-x
snap-backupIf dump
honors the “nodump”
flag (UF_NODUMP
), files with the
“nodump” flag will not be backed up. If a directory has the
“nodump” flag, this directory and any file or directory under
it will not be backed up.
dump
requires operator intervention on
these conditions: end of tape, end of dump, tape write error, tape open
error or disk read error (if there are more than a threshold of 32). In
addition to alerting all operators implied by the -n
option, dump
interacts with the operator on
dump
's control terminal at times when
dump
can no longer proceed, or if something is
grossly wrong. All questions dump
poses
must be answered by typing “yes” or
“no”, appropriately.
Since making a dump involves a lot of time and effort for full
dumps, dump
checkpoints itself at the start of each
tape volume. If writing that volume fails for some reason,
dump
will, with operator permission, restart itself
from the checkpoint after the old tape has been rewound and removed, and a
new tape has been mounted.
dump
tells the operator what is going on
at periodic intervals, including usually low estimates of the number of
blocks to write, the number of tapes it will take, the time to completion,
and the time to the tape change. The output is verbose, so that others know
that the terminal controlling dump
is busy, and will
be for some time.
In the event of a catastrophic disk event, the time required to restore all the necessary backup tapes or files to disk can be kept to a minimum by staggering the incremental dumps. An efficient method of staggering incremental dumps to minimize the number of tapes follows:
/sbin/dump -0u -f /dev/nrst1 /usr/src
This should be done at set intervals, say once a month or once every two months, and on a set of fresh tapes that is saved forever.
3 2 5 4 7 6 9 8 9 9 ...
For the daily dumps, it should be possible to use a fixed number of tapes for each day, used on a weekly basis. Each week, a level 1 dump is taken, and the daily Hanoi sequence repeats beginning with 3. For weekly dumps, another fixed set of tapes per dumped file system is used, also on a cyclical basis.
After several months or so, the daily and weekly tapes should get rotated out of the dump cycle and fresh tapes brought in.
If dump
receives a
SIGINFO
signal (see the “status”
argument of stty(1)) whilst a
backup is in progress, statistics on the amount completed, current transfer
rate, and estimated finished time, will be written to the standard error
output.
The historic alternate name rdump
was once
required when dumping to a remote host. This functionality is now built into
dump
itself.
dump
.
TAPE
dump
will use the
device specified via TAPE
as the dump device.
TAPE
may be of the form “tapename”,
“host:tapename”, or “user@host:tapename”.RCMD_CMD
dump
will use RCMD_CMD
rather than rsh(1) to invoke
rmt(8) on the remote
machine.TIMEFORMAT
-t
option. TIMEFORMAT
is a
string containing embedded formatting commands for
strftime(3). The total
formatted string is limited to about 80 characters, if this limit is
exceeded then “ERROR: TIMEFORMAT too long, reverting to
default” will be printed and the time format will revert to the
default one. If TIMEFORMAT
is not set then the
format string defaults to “%T %Z”_PATH_DEFTAPE
in /usr/include/paths.h.dump
exits with zero status on success.
Startup errors are indicated with an exit code of 1; abnormal termination is
indicated with an exit code of 3.
dump
command appeared in
Version 4 AT&T UNIX.
The -i
flag was inspired by the
-x
flag from Sun's Solstice Backup utility.
dump
with the -W
or
-w
options does not report file systems that have
never been recorded in /etc/dumpdates, even if
listed in /etc/fstab.dump
knew about the dump
sequence, kept track of the tapes scribbled on, told the operator which
tape to mount when, and provided more assistance for the operator running
restore(8).March 25, 2019 | NetBSD 9.4 |