dump(1M) DG/UX R4.11MU05 dump(1M)
NAME
dump - incremental file system dump
SYNOPSIS
/usr/sbin/dump [ key [ argument ... ] special ]
DESCRIPTION
The dump command copies to magnetic tape all files changed after a
certain date in a particular file system. (You may prefer to use the
dump2(1M) command rather than dump because dump2 is faster;
otherwise, there is no disadvantage to using dump.)
Note that dump on systems with DG/UX information security does not
save security attributes. Thus, if restore(1M) is used to restore
files saved with dump, all security attributes will be set based upon
the security attributes of the restoring process. It is recommended
that dump2(1) be used to make a trusted archive.
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 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 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
DIAGNOSTICS
Many, and verbose.
SEE ALSO
restore(1M), fstab(4).
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.
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.
Licensed material--property of copyright holder(s)