4.4BSD/usr/share/man/cat8/rdump.0
DUMP(8) BSD System Manager's Manual DUMP(8)
NNAAMMEE
dduummpp - filesystem backup
SSYYNNOOPPSSIISS
dduummpp [00112233445566778899BBbbhhffuussTTddWWnn [_a_r_g_u_m_e_n_t _._._.]] [_f_i_l_e_s_y_s_t_e_m]
DDEESSCCRRIIPPTTIIOONN
DDuummpp examines files on a filesystem and determines which files need to be
backed up. These files are copied to the given disk, tape or other stor-
age medium for safe keeping (see the ff option below for doing remote
backups). A dump that is larger than the output medium is broken into
multiple volumes. On most media the size is determined by writing until
an end-of-media indication is returned. On media that cannot reliably
return an end-of-media indication (such as some cartridge tape drives)
each volume is of a fixed size; the actual size is determined by the tape
size and density and/or block count options below. By default, the same
output file name is used for each volume after prompting the operator to
change media.
The following options are supported by dduummpp::
00--99 Dump levels. A level 0, full backup, guarantees the entire file
system is copied (but see also the hh option below). A level number
above 0, incremental backup, tells dump to copy all files new or
modified since the last dump of the same or lower level. The de-
fault level is 9.
BB _r_e_c_o_r_d_s
The number of dump records per volume. This option overrides the
calculation of tape size based on length and density.
bb _b_l_o_c_k_s_i_z_e
The number of kilobytes per dump record.
hh _l_e_v_e_l
Honor the user ``nodump'' flag only for dumps at or above the given
_l_e_v_e_l. The default honor level is 1, so that incremental backups
omit such files but full backups retain them.
ff _f_i_l_e
Write the backup to _f_i_l_e; _f_i_l_e may be a special device file like
_/_d_e_v_/_r_m_t_1_2 (a tape drive), _/_d_e_v_/_r_s_d_1_c (a disk drive), an ordinary
file, or `--' (the standard output). Multiple file names may be
given as a single argument separated by commas. Each file will be
used for one dump volume in the order listed; if the dump requires
more volumes than the number of names given, the last file name
will used for all remaining volumes after prompting for media
changes. If the name of the file is of the form ``host:file'', or
``user@host:file'', dduummpp writes to the named file on the remote
host using rmt(8).
dd _d_e_n_s_i_t_y
Set tape density to _d_e_n_s_i_t_y. The default is 1600BPI.
nn Whenever dduummpp requires operator attention, notify all operators in
the group ``operator'' by means similar to a wall(1).
ss _f_e_e_t
Attempt to calculate the amount of tape needed at a particular den-
sity. If this amount is exceeded, dduummpp prompts for a new tape. It
is recommended to be a bit conservative on this option. The de-
fault tape length is 2300 feet.
uu Update the file _/_e_t_c_/_d_u_m_p_d_a_t_e_s after a successful dump. The format
of _/_e_t_c_/_d_u_m_p_d_a_t_e_s is readable by people, consisting of one free
format record per line: filesystem name, increment level and
ctime(3) format dump date. There may be only one entry per
filesystem at each level. The file _/_e_t_c_/_d_u_m_p_d_a_t_e_s may be edited to
change any of the fields, if necessary.
TT _d_a_t_e
Use the specified date as the starting time for the dump instead of
the time determined from looking in _/_e_t_c_/_d_u_m_p_d_a_t_e_s. The format of
date is the same as that of ctime(3). This option is useful for
automated dump scripts that wish to dump over a specific period of
time. The TT option is mutually exclusive from the uu option.
WW DDuummpp 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 WW option causes dduummpp 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 WW op-
tion is set, all other options are ignored, and dduummpp exits immedi-
ately.
ww Is like W, but prints only those filesystems which need to be
dumped.
DDuummpp 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 nn key, dduummpp interacts with the operator on _d_u_m_p_'_s control
terminal at times when dduummpp can no longer proceed, or if something is
grossly wrong. All questions dduummpp poses _m_u_s_t be answered by typing
``yes'' or ``no'', appropriately.
Since making a dump involves a lot of time and effort for full dumps,
dduummpp checkpoints itself at the start of each tape volume. If writing
that volume fails for some reason, dduummpp 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.
DDuummpp 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 dduummpp is busy, and will be for some time.
In the event of a catastrophic disk event, the time required to restore
all the necessary backup tapes or files to disk can be kept to a minimum
by staggering the incremental dumps. An efficient method of staggering
incremental dumps to minimize the number of tapes follows:
++oo Always start with a level 0 backup, for example:
/etc/dump 0uf /dev/nrst1 /usr/src
This should be done at set intervals, say once a month or once
every two months, and on a set of fresh tapes that is saved
forever.
++oo After a level 0, 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, it should be possible to use a fixed num-
ber of tapes for each day, used on a weekly basis. Each week,
a level 1 dump is taken, and the daily Hanoi sequence repeats
beginning with 3. For weekly dumps, another fixed set of tapes
per dumped file system is used, also on a cyclical basis.
After several months or so, the daily and weekly tapes should get rotated
out of the dump cycle and fresh tapes brought in.
FFIILLEESS
/dev/rmt8 default tape unit to dump to
/etc/dumpdates dump date records
/etc/fstab dump table: file systems and frequency
/etc/group to find group _o_p_e_r_a_t_o_r
SSEEEE AALLSSOO
restore(8), rmt(8), dump(5), fstab(5)
DDIIAAGGNNOOSSTTIICCSS
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.
BBUUGGSS
Fewer than 32 read errors on the filesystem are ignored. Each reel re-
quires a new process, so parent processes for reels already written just
hang around until the entire tape is written.
DDuummpp with the WW or ww options does not report filesystems that have never
been recorded in _/_e_t_c_/_d_u_m_p_d_a_t_e_s, even if listed in _/_e_t_c_/_f_s_t_a_b.
It would be nice if dduummpp knew about the dump sequence, kept track of the
tapes scribbled on, told the operator which tape to mount when, and pro-
vided more assistance for the operator running restore.
HHIISSTTOORRYY
A dduummpp command appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution June 16, 1993 3