4.3BSD-UWisc/man/cat8/dump.8
DUMP(8) UNIX Programmer's Manual DUMP(8)
NAME
dump - incremental file system dump
SYNOPSIS
/etc/dump [ key [ _a_r_g_u_m_e_n_t ... ] filesystem ]
DESCRIPTION
_D_u_m_p copies to magnetic tape all files changed after a cer-
tain date in the _f_i_l_e_s_y_s_t_e_m. The _k_e_y specifies the date and
other options about the dump. _K_e_y 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 /_e_t_c/_d_u_m_p_d_a_t_e_s
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 _a_r_g_u_m_e_n_t file instead of the
tape. If the name of the file is ``-'', _d_u_m_p writes to
standard output.
u If the dump completes successfully, write the date of
the beginning of the dump on file /_e_t_c/_d_u_m_p_d_a_t_e_s. This
file records a separate date for each filesystem and
each dump level. The format of /_e_t_c/_d_u_m_p_d_a_t_e_s is read-
able by people, consisting of one free format record
per line: filesystem name, increment level and _c_t_i_m_e(_3)
format dump date. /_e_t_c/_d_u_m_p_d_a_t_e_s 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 _a_r_g_u_m_e_n_t. When
the specified size is reached, _d_u_m_p 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 _a_r_g_u_m_e_n_t. This is used in calculating the
amount of tape used per reel. The default is 1600.
W _D_u_m_p tells the operator what file systems need to be
dumped. This information is gleaned from the files
/_e_t_c/_d_u_m_p_d_a_t_e_s and /_e_t_c/_f_s_t_a_b. The W option causes _d_u_m_p
to print out, for each file system in /_e_t_c/_d_u_m_p_d_a_t_e_s
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 _d_u_m_p
exits immediately.
w Is like W, but prints only those filesystems which need
to be dumped.
Printed 12/27/86 May 23, 1986 1
DUMP(8) UNIX Programmer's Manual DUMP(8)
n Whenever _d_u_m_p requires operator attention, notify by
means similar to a _w_a_l_l(1) all of the operators in the
group "operator".
If no arguments are given, the _k_e_y is assumed to be 9u and a
default file system is dumped to the default tape.
_D_u_m_p 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,
_d_u_m_p interacts with the operator on _d_u_m_p'_s control terminal
at times when _d_u_m_p can no longer proceed, or if something is
grossly wrong. All questions _d_u_m_p poses must be answered by
typing "yes" or "no", appropriately.
Since making a dump involves a lot of time and effort for
full dumps, _d_u_m_p checkpoints itself at the start of each
tape volume. If writing that volume fails for some reason,
_d_u_m_p 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.
_D_u_m_p tells the operator what is going on at periodic inter-
vals, 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 control-
ling _d_u_m_p 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 sys-
tem 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 _o_p_e_r_a_t_o_r
Printed 12/27/86 May 23, 1986 2
DUMP(8) UNIX Programmer's Manual DUMP(8)
SEE ALSO
restore(8), dump(5), fstab(5)
DIAGNOSTICS
Many, and verbose.
Dump exits with zero status on success. Startup errors are
indicated with an exit code of 1; abnormal termination is
indicated with an exit code of 3.
BUGS
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.
_D_u_m_p with the W or w options does not report filesystems
that have never been recorded in /etc/dumpdates, even if
listed in /etc/fstab.
It would be nice if _d_u_m_p 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 _r_e_s_t_o_r_e.
Printed 12/27/86 May 23, 1986 3