Manual page for DUMP(8)
dump, rdump - incremental file system dump
SYNOPSIS
/usr/etc/dump
[
options
[
arguments
] ]
filesystem
/usr/etc/dump
[
options
[
arguments
] ]
filename
...
/usr/etc/rdump
[
options
[
arguments
] ]
filesystem
/usr/etc/rdump
[
options
[
arguments
] ]
filename
...
DESCRIPTION
dump
backs up all files in
filesystem,
or files changed after a certain date,
or a specified set of files and directories,
to magnetic tape, diskettes, or files.
options
is a string that specifies
dump
options, as shown below.
Any
arguments
supplied for specific options are given as subsequent words on
the command line, in the same order as that of the
options
listed.
If
dump
is called as
rdump,
the dump device defaults to
dumphost:/dev/rmt8.
If no
options
are given, the default is
9u.
dump
is normally used to back up a complete filesystem. To restrict the dump
to a specified set of files and directories on one filesystem, list
their names on the command line. In this mode the dump level is
set to
0
and the
u
option is ignored.
OPTIONS
- 0-9
-
The ``dump level.''
All files in the
filesystem
that have been modified since the last
dump
at a lower dump level are copied to the volume.
For instance, if you did a
``level 2''
dump on Monday, followed by a
``level 4''
dump on Tuesday, a subsequent
``level 3''
dump on Wednesday would contain
all files modified or added
since the ``level 2''
(Monday) backup.
A ``level 0''
dump copies the entire filesystem to the dump volume.
- a archive-file
-
Create a dump table-of-contents archive in the specified file,
archive-file.
This file can be used by
restore.8
to determine whether a file is present on a dump tape,
and if so, on which volume it resides.
For further information on the use of a dump archive file, see
restore.8
- b factor
-
Blocking factor.
Specify the blocking factor for tape writes.
The default is 20 blocks per write.
Note: the blocking factor is
specified in terms of 512 bytes blocks, for compatibility with
tar.1
The default blocking factor for tapes of
density 6250 BPI and greater
is 64.
The default blocking factor for cartridge tapes
(c
option specified) is 126.
The highest blocking
factor available with most tape drives is 126.
- c
-
Cartridge.
Use a cartridge instead of the standard half-inch reel.
This sets the density to 1000 BPI,
the blocking factor to 126, and the length to 425 feet.
This option also sets the ``inter-record gap''
to the appropriate length.
When cartridge tapes are used, and this option is
not
specified,
dump
will slightly miscompute the size of the tape.
If the
b,
d,
s
or
t
options are specified with this option,
their values will override the defaults set by this
option.
- d bpi
-
Tape density.
The density of the tape, expressed in
BPI,
is taken from
bpi.
This is used to keep a running tab on
the amount of tape used per reel.
Default densities are:
-
-
- 1/2" tape
-
1600 BPI
- 1/4" cartridge
-
1000 BPI
- 2.3-Gbyte 8mm tape
-
54,000 BPI
-
Unless a higher density is specified explicitly,
dump
uses its default density -- even if the tape drive is capable of
higher-density operation (for instance, 6250 BPI).
Note: the density specified should correspond to the density of the
tape device being used, or
dump
will not be able to handle end-of-tape properly.
The
d
option is not compatible with the
D
option.
- D
-
Diskette. Specify diskette as the dump media.
- f dump-file
-
Dump file.
Use
dump-file
as the file to dump to, instead of
/dev/rmt8.
If
dump-file
is specified as
`-',
dump to the standard output.
If the file name argument is of the form
machine:device,
dump to a
remote machine.
Since
dump
is normally run by
root,
the name of the local machine must appear in the
.rhosts
file of the remote machine.
If the file name argument is of the form
user@machine:device,
dump
will attempt to execute as the specified user on the remote machine.
The specified user must have a
.rhosts
file on the remote machine that allows root from the local machine.
If
dump
is called as
rdump,
the dump device defaults to
dumphost:/dev/rmt8.
To direct the output to a desired remote machine,
set up an alias for
dumphost in the file
/etc/hosts.
- n
-
Notify.
When this option is specified, if
dump
requires attention, it sends a terminal message
(similar to
wall.1
to all operators in the ``operator'' group.
- s size
-
Specify the
size
of the volume being dumped to. When the specified size is reached,
dump
waits for you to change the volume.
dump
interprets the specified size as the length in
feet for tapes, and cartridges and
as the number of 1024 byte blocks for diskettes.
The following are
defaults:
-
-
- 1/2" tape
-
2300 feet
- 60-Mbyte 1/4" cartridge
-
425 feet
- 150-Mbyte 1/4" cartridge
-
700 feet
- 2.3-Gbyte 8mm
-
6000 feet
- diskette
-
1422 blocks (Corresponds
to a 1.44-Mbyte diskette, with one cylinder reserved for bad block information.)
- t tracks
-
Specify the number of tracks for a cartridge tape.
The
t
option is not compatible with the
D
option.
The following are
defaults:
-
-
- 60-Mbyte 1/4" cartridge (Sun2 only)
-
4 tracks
- 60-Mbyte 1/4" cartridge (all other platforms)
-
9 tracks
- 150-Mbyte 1/4" cartridge
-
18 tracks
- u
-
Update the dump record.
Add an entry to the file
/etc/dumpdates,
for each filesystem successfully dumped that includes the filesystem
name, date, and dump level.
This file can be edited by the super-user.
- v
-
After writing each volume of the dump,
the media is rewound and is verified against the filesystem being dumped.
If any discrepancies are found,
dump will respond as if a write error had occurred;
the operator will be asked to mount new media,
and dump will attempt to rewrite the volume.
Note that
any
change to the filesystem, even the update of the access time
on a file will cause the verification to fail.
Thus, the verify option can only be used on a quiescent filesystem.
- w
-
List the filesystems that need backing up.
This
information is gleaned from the files
/etc/dumpdates
and
/etc/fstab.
When the
w
option is used, all other options
are ignored.
After reporting,
dump
exits immediately.
- W
-
Like
w,
but includes all filesystems that appear in
/etc/dumpdates,
along with information about their most recent dump dates and levels.
Filesystems that need backing up are highlighted.
FILES
- /dev/rmt8
-
default unit to dump to
- dumphost:/dev/rmt8
-
default remote unit to dump to if called as
rdump
- /dev/rst*
-
Sun386i cartridge tape dump device
- /dev/rfd0a
-
Sun386i 1.44 megabyte 3.5-inch high density diskette drive dump device
- /dev/rfdl0a
-
Sun386i 720 kilobyte 3.5-inch low density diskette drive dump device
- /dev/rfd0c
-
Sun386i 1.44 megabyte 3.5-inch high density diskette drive dump device
- /dev/rfdl0c
-
Sun386i 720 kilobyte 3.5-inch low density diskette drive dump device
- /etc/dumpdates
-
dump date record
- /etc/fstab
-
dump table: file systems and frequency
- /etc/group
-
to find group
operator
- /etc/hosts
-
SEE ALSO
bar.1
fdformat.1
tar.1
wall.1
dump.5
fstab.5
restore.8
shutdown.8
DIAGNOSTICS
While running,
dump
emits many verbose messages.
Exit Codes
- 0
-
Normal exit.
- 1
-
Startup errors encountered.
- 3
-
Abort - no checkpoint attempted.
BUGS
Fewer than 32 read errors on the file system are ignored.
Each reel requires a new process, so parent processes for
reels already written just hang around
until the entire tape is written.
It is recommended that incremental dumps also be performed with
the system running in single-user mode.
dump
does not support multi-file multi-volume tapes.
EXAMPLES
Here are some examples of arguments which produce satisfactory
results on a number of typical tape drives.
Note that individual options can be in any order; however, the
position of each following argument depends on the relative
position of each option.
-
- 60-MByte cartridge (Sun2 only):
-
dump cdst 1000 425 4
- 60-MByte cartridge:
-
dump cdst 1000 425 9
- 150-MByte cartridge:
-
dump cdst 1000 700 18
- 1/2" tape:
-
dump dsb 1600 2300 126
- 2.3-GByte 8mm tape:
-
dump dsb 54000 6000 126
To make a full dump of a root filesystem on sd3, on a 150-MByte
cartridge tape st0, use:
-
dump 0cdstfu 1000 700 18 /dev/rst0 /dev/sd3a
To make and verify an incremental dump at level 5 of the usr
partition of sd3, on a 1/2" reel tape st1:
-
dump 5dsbfuv 1600 2300 126 /dev/rst1 /dev/sd3g
To make a full backup of the entire disk sd3, on a 2.3-GByte
8mm tape st2, use:
-
dump 0dsbfu 54000 6000 126 /dev/rst2 /dev/sd3c
NOTES
Operator Intervention
dump
requires operator intervention on these conditions:
end of volume, end of dump, volume write error, volume 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,
as appropriate.
Since backing up a disk can involve a lot of time and effort,
dump
checkpoints at the start of each volume.
If writing that volume fails for some reason,
dump
will, with operator permission, restart itself from the
checkpoint after a defective volume has been replaced.
dump
reports periodically, and in verbose fashion.
Each report
includes estimates of the percentage of the dump completed
and how long it will take to complete the dump.
The estimated time is given as
hours:minutes.
Suggested Dump Schedule
It is vital to perform full, ``level 0'',
dumps at regular intervals.
When performing a full dump, bring the machine down to
single-user mode using
shutdown.8
While preparing for a full dump, it is a good idea to clean the
tape drive and heads.
Incremental dumps allow for convenient backup and recovery on a more
frequent basis of active files, with a minimum of media and time.
However there are some tradeoffs.
First, the interval between backups
should be kept to a minimum (once a day at least).
To guard against
data loss as a result of a media failure (a rare, but possible
occurrence), it is a good idea to capture active files on (at least)
two sets of dump volumes.
Another consideration
is the desire to keep unnecessary
duplication of files to a minimum to save both operator time and media
storage.
A third consideration is the ease with which a particular
backed-up version of a file can be located and restored.
The following four-week schedule offers a reasonable tradeoff between
these goals.
-
Sun Mon Tue Wed Thu Fri
Week 1: Full 5 5 5 5 3
Week 2: 5 5 5 5 3
Week 3: 5 5 5 5 3
Week 4: 5 5 5 5 3
Although the Tuesday -- Friday incrementals contain ``extra
copies''
of files from Monday, this scheme assures that any file
modified during the week can be recovered from the previous
day's incremental dump.
Process Priority of dump
dump
uses multiple processes to allow it to
read from the disk and write to the
media concurrently.
Due to the way it
synchronizes between these processes,
any attempt to run dump with a
nice
(process priority) of `-5' or better will likely make
dump
run
slower
instead of faster.
Created by unroff & hp-tools.
© somebody (See intro for details). All Rights Reserved.
Last modified 11/5/97