dump(1m) DG/UX 4.30 dump(1m)
NAME
dump - incremental file system dump
SYNOPSIS
/etc/dump [ key [ argument ... ] special ]
DESCRIPTION
The dump command copies to magnetic tape all files changed
after a certain date in a particular file system. Special
is the pathname of a special file referring to a device
containing a file system. Key specifies the date and other
options about the dump. The key consists of characters from
the set 0123456789bcdfgJnsuWwz:
0-9 Indicate the dump level. All files modified since the
last date stored in the file /etc/dumpdates for the
same file system at lesser levels will be dumped. If
no date is determined by the level, the beginning of
Jan. 1, 1970, GMT, is assumed; thus the option 0 dumps
the entire file system.
b Specify blocking factor, the number of 1024-byte blocks
per tape record. Default is 10; maximum is 32.
Ideally, this number will match the optimal blocking
factor for the tape device.
g Specify a memory buffer size expressed as 1K blocks.
Default is set to the value of the -b option (or 10, if
-b is not used). The maximum is 2048. The buffer must
be at least the size and a multiple of the -b value and
may also be limited by memory available. Note that
increasing this buffer will allow you to stream
devices.
c The tape used is a cartridge tape. Dump(1M) considers
this factor when it determines how much it can write on
one tape. See also the s option.
d Take the density of the tape, expressed in bits per
inch(bpi), from the next argument. This is used in
calculating how much can be written to each tape. The
default is 1600 bpi.
f Place the dump on the next argument file instead of the
tape. If you have DG TCP/IP (DG/UX), you can use this
option to dump to a remote device. For example,
dump 0f sys:/dev/rmt/0 /root
lets you dump the root filesystem to the tape device
"0" on system "sys." To do this, you must be logged in
as root on your own system, and your system must have
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an entry in the remote host's /.rhosts file.
J Convert the old, obsolete format to the new format.
All other options are ignored, and dump terminates
immediately. Invoke this option only when the old
/etc/ddate files are updated to the new /etc/dumpdates
format.
n Notify an operator (as in wall(1M)) whenever a response
is required at the operator's console. /etc/group must
contain an entry for "operator."
s Specify the size of the dump tape in feet. The number
of feet is taken from the next argument. When the
specified size is reached, dump waits for the tape to
be changed. The default tape size is 2300 feet. Type
of tape is also a factor in dump's calculation of tape
length; see the c option.
u Write the date of the beginning of the dump on file
/etc/dumpdates, if the dump completes successfully.
This file records a separate date for each file system
and each dump level. You can read the format of
/etc/dumpdates, which consists of one free format
record per line: file system name, increment level,
and ctime(3)-format dump date. You can edit
/etc/dumpdates to change any of the fields. Note that
/etc/dumpdates is formatted differently from previous
versions of dump in /etc/ddate, although it contains
identical information. This option may cause errors if
your /etc/dumpdates file contains entries generated by
the dump2(1m) command. See the NOTES section.
W Tell the operator what file systems need to be dumped.
This information is gleaned from the files
/etc/dumpdates and /etc/fstab. Dump prints out the
most recent dump date and level for each file system in
/etc/dumpdates, and highlights those file systems that
should be dumped. All other options are ignored, and
dump exits immediately. This option may cause errors
if your /etc/dumpdates file contains entries generated
by the dump2(1m) command. See the NOTES section.
w Do as W does, but print only those file systems that
need to be dumped. This option may cause errors if
your /etc/dumpdates file contains entries generated by
the dump2(1m) command. See the NOTES section.
z Print the inode numbers of dumped files on the standard
output.
If no arguments are given, key is assumed to be 9u and a
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dump(1m) DG/UX 4.30 dump(1m)
default file system is dumped to the default tape.
Dump and restore support symbolic links and control point
directories.
Dump requires operator intervention on end of tape, end of
dump, tape write error, tape open error, or disk read error
(if there are more than 32 errors). In addition to alerting
all operators (with the n key), dump interacts with the
operator on dump's control terminal when dump can no longer
proceed, or if something is grossly wrong. All questions
dump poses must be answered by typing yes or no.
Since making a full dump involves a lot of time and effort,
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.
At periodic intervals, dump tells the operator what is going
on, usually including 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.
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,
which is saved indefinitely, is taken on a set of fresh
tapes.
FILES
/etc/dumpdates New format dump date record
/etc/fstab Dump table: file systems and frequency
/etc/group To find group operator
SEE ALSO
restore(1m), fstab(4).
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dump(1m) DG/UX 4.30 dump(1m)
NOTES
The dump command will return an error if you invoke it with
the u, W, or w options after the /etc/dumpdates file has
been written to with a dump2 -u command (see dump2(1m)).
Before using dump with the u, W, or w options in such cases,
you should first remove all entries from the /etc/dumpdates
file.
DIAGNOSTICS
Many, and verbose.
BUGS
Sizes are based on 1600 BPI blocked tape. Fewer than 32
read errors on the file system are ignored. Since each tape
requires a new process, parent processes for tapes already
written continue until the entire tape is written.
Dump should know about the dump sequence, keep track of the
tapes used, tell the operator which tape to mount and when,
and provide more help to the operator running restore.
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