DUMP(8) GENIX Programmer's Manual DUMP(8)
NAME
dump - incremental file system dump
SYNOPSIS
/etc/dump [ key [ argument ... ] filesystem ]
DESCRIPTION
Dump copies, usually to magnetic tape, all files in the filesystem
changed after a certain date. The key specifies the date and other
options about the dump. Key consists of characters from the set
0123456789fuJsdWn.
Note: Dump will copy any filesystem anywhere. A bad command line
can copy one filesystem to another, destroying the file system
copied.
0-9 This number is the `dump level'. All files, modified since the
last date, and 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.
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. Note that
/etc/dumpdates is in a format different from that which previ-
ous versions of dump maintained in /etc/ddate, although the
information content is identical.
J This option is intended to be invoked only when the old format
/etc/ddate files are updated to the new format /etc/dumpdates
format. The effect of this option is to convert between the
old, obsolete format and to the new format. If the J option is
invoked, all other options are ignored, and dump terminates
immediately.
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.
Printed 11/16/83 1
DUMP(8) GENIX Programmer's Manual DUMP(8)
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.
n Whenever dump requires operator attention, notify by means
similar to a wall(1) all of the operators in the group "opera-
tor".
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.
Because 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 lev-
els:
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
Printed 11/16/83 2
DUMP(8) GENIX Programmer's Manual DUMP(8)
saved forever.
FILES
/dev/rdc1g default filesystem to dump from
/dev/rtc0 default tape unit to dump to
/etc/ddate old format dump date record (obsolete after -J option)
/etc/dumpdates new format dump date record
/etc/fstab Dump table: file systems and frequency
/etc/group to find group operator
SEE ALSO
restor(8), dump(5), dumpdir(8), fstab(5)
DIAGNOSTICS
Many and verbose.
BUGS
Sizes are based on 1600 BPI blocked tape; the raw magtape device has
to be used to approach these densities. 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.
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 restor.
Size and density are not meaningful with a streaming tape drive.
Printed 11/16/83 3