DUMP(8) MachTen Programmer’s Manual DUMP(8)

NAME
dump - incremental file system dump

SYNOPSIS
dump [ key [ argument ... ] filesystem ]

DESCRIPTION
Dump copies to magnetic tape all files changed after a
certain date in the filesystem. The key specifies the
date and other options about the dump. Key consists of
characters from the set 0123456789fusdWn.

0-9 This number is the ‘dump level’. All files modified
since the last date 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. If the name of the file is ‘‘-’’, dump
writes to standard output.

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.

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. 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 "operator".

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 thresh-
old 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", appropri-
ately.

Since 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 rea-
son, 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 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 is taken on a set of fresh tapes that is
saved forever.

FILES
/dev/rrp1g default filesystem to dump from
/dev/rmt8 default tape unit to dump to
/etc/dumpdates new format dump date record
/etc/fstab dump table: file systems and frequency
/etc/group to find group operator