DUMP(1M) DUMP(1M)
NAME
dump - incremental file system dump
SYNOPSIS
dump [ key [ argument ... ] filesystem ]
DESCRIPTION
Dump copies to magnetic tape all files changed after a cer-
tain date in the filesystem. The key specifies the date and
other options about the dump. Key consists of characters
from the set 0123456789fusd.
f Place the dump on the next argument file instead of the
tape.
u If the dump completes successfully, write the date of
the beginning of the dump on file `/etc/ddate'. This
file records a separate date for each filesystem and
each dump level.
0-9 This number is the `dump level'. All files modified
since the last date stored in the file `/etc/ddate' 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.
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, the dump will wait for
reels to be changed. The default 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 write. The default is 1600.
If no arguments are given, the key is assumed to be 9u and a
default file system is dumped to the default tape.
Now a short suggestion on how perform dumps. Start with a
full level 0 dump
dump 0u
Next, periodic level 9 dumps should be made on an exponen-
tial progression of tapes. (Sometimes called Tower of Hanoi
- 1 2 1 3 1 2 1 4 ... tape 1 used every other time, tape 2
used every fourth, tape 3 used every eighth, etc.)
dump 9u
DUMP(1M) DUMP(1M)
When the level 9 incremental approaches a full tape (about
78000 blocks at 1600 BPI blocked 20), a level 1 dump should
be made.
dump 1u
After this, the exponential series should progress as unin-
terrupted. These level 9 dumps are based on the level 1
dump which is based on the level 0 full dump. This progres-
sion of levels of dump can be carried as far as desired.
FILES
default filesystem and tape vary with installation.
/etc/ddate: record dump dates of filesystem/level.
SEE ALSO
restor(1), dump(5), dumpdir(1)
DIAGNOSTICS
If the dump requires more than one tape, it will ask you to
change tapes. Reply with a new-line when this has been
done.
BUGS
Sizes are based on 1600 BPI blocked tape. The raw magtape
device has to be used to approach these densities. Read
errors on the filesystem are ignored. Write errors on the
magtape are usually fatal.