dump(1M) dump(1M)
NAME
dump - incremental file system dump
SYNOPSIS
/etc/dump [key[argument...]filesystem
DESCRIPTION
dump copies to magnetic tape all files changed after a
certain date in the filesystem. The key specifies the date
and other options about the dump. key consists of
characters from the set 0123456789fusdWn.
0-9 This number is the `dump level'. All files modified
since the last date stored in the file /etc/dumpdates
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 option 0 causes
the entire filesystem to be dumped.
f Place the dump on the next argument file instead of the
tape. If the name of the file is ``-'', dump writes to
standard output.
u If the dump completes successfully, write the date of
the beginning of the dump on file /etc/dumpdates. This
file records a separate date for each filesystem and
each dump level. The format of /etc/dumpdates is
readable by people, consisting of one free format
record per line: filesystem name, increment level and
ctime(3) format dump date. /etc/dumpdates may be edited
to change any of the fields, if necessary.
s The size of the dump tape is specified in feet. The
number of feet is taken from the next argument. When
the specified size is reached, dump will wait for reels
to be changed. The default tape size is 2300 feet.
d The density of the tape, expressed in BPI, is taken
from the next argument. This is used in calculating the
amount of tape used per reel. The default is 1600.
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 Is like W, but prints only those filesystems which need
to be dumped.
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dump(1M) dump(1M)
n Whenever dump requires operator attention, notify by
means similar to a wall(1) all of the operators in the
group operator.
If no arguments are given, the key is assumed to be 9u and a
default file system is dumped to the default tape.
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 key,
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.
Now a short suggestion on how to perform dumps. Start with
a full level 0 dump
dump 0un
Next, dumps of active file systems are taken on a daily
basis, using a modified Tower of Hanoi algorithm, with this
sequence of dump levels:
3 2 5 4 7 6 9 8 9 9 ...
For the daily dumps, a set of 10 tapes per dumped file
system is used on a cyclical basis. Each week, a level 1
dump is taken, and the daily Hanoi sequence repeats with 3.
For weekly dumps, a set of 5 tapes per dumped file system is
used, also on a cyclical basis. Each month, a level 0 dump
is taken on a set of fresh tapes that is saved forever.
FILES
/etc/dump
/dev/rrp1g default filesystem to dump from
/dev/rmt8 default tape unit to dump to
/etc/dumpdates new format dump date record
/etc/fstab dump table: file systems and frequency
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dump(1M) dump(1M)
/etc/group to find group operator
SEE ALSO
restore(1m), dump(4), fstab(4)
DIAGNOSTICS
Many, and verbose.
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.
BUGS
Fewer than 32 read errors on the filesystem are ignored.
Each reel requires a new process, so parent processes for
reels already written just hang around until the entire tape
is written.
dump with the W or w options does not report filesystems
that have never been recorded in /etc/dumpdates, even if
listed in /etc/fstab.
It would be nice if 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.
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