1DUMP(8) System Manager's Manual DUMP(8)
2
6 dump - incremental file system dump
7
9 dump [0123456789BchfusTdWwn [argument ...]] [filesystem]
10
12 Dump copies to magnetic tape all files changed after a certain date in
13 the filesystem.
14 The following options are supported by dump:
16 0-9 This number is the `dump level'. All files modified since the
18 last date stored in the file /etc/dumpdates for the same filesys‐
19 tem at lesser levels will be dumped. If no date is determined by
20 the level, the beginning of time is assumed; thus the option 0
21 causes the entire filesystem to be dumped.
22 B records
24 The number of dump records per volume. This option overrides the
25 calculation of tape size based on length and density.
26 c This option requires no further options. Used to specify that the
28 tape is a cartridge drive rather than a 9-track.
29 h level
31 Honor the user 'nodump' flags only for dumps at or above the given
32 level. The default honor level is 1, so that incremental backups
33 omit such files but full backups retain them.
34 f Place the dump on the next argument file instead of the tape. If
36 '-' is given then standard out (stdout) is written to.
37 u If the dump completes successfully, write the date of the begin‐
39 ning of the dump on file /etc/dumpdates. This file records a sep‐
40 arate date for each filesystem and each dump level. The format of
41 /etc/dumpdates is readable by people, consisting of one free for‐
42 mat record per line: filesystem name, increment level and ctime(3)
43 format dump date. /etc/dumpdates may be edited to change any of
44 the fields, if necessary. Note that /etc/dumpdates is in a format
45 different from that which previous versions of dump maintained in
46 /etc/ddate, although the information content is identical.
47 s The size of the dump tape is specified in feet. The number of
49 feet is taken from the next argument. When the specified size is
50 reached, dump will wait for reels to be changed. The default tape
51 size is 2300 feet.
52 d The density of the tape, expressed in BPI, is taken from the next
54 argument. This is used in calculating the amount of tape used per
55 reel. The default is 1600.
56 T date
58 Use the specified date as the starting time for the dump instead
59 of the time determined from looking in /etc/dumpdates. The format
60 of date is the same as that of ctime(3). This option is useful
61 for automated dump scripts that wish to dump over a specific
62 period of time. The T option is mutually exclusive with the u
63 option.
64 W Dump tells the operator what file systems need to be dumped. This
66 information is gleaned from the files /etc/dumpdates and
67 /etc/fstab. The W option causes dump to print out, for each file
68 system in /etc/dumpdates the most recent dump date and level, and
69 highlights those file systems that should be dumped. If the W
70 option is set, all other options are ignored, and dump exits imme‐
71 diately.
72 w Is like W, but prints only those filesystems which need to be
74 dumped.
75 n Whenever dump requires operator attention, notify by means similar
77 to a wall(1) all of the operators in the group “operator”.
78 If no arguments are given, the key is assumed to be 9u and a default
80 file system is dumped to the default tape.
81 Dump requires operator intervention on these conditions: end of tape,
83 end of dump, tape write error, tape open error or disk read error (if
84 there are more than a threshold of 32). In addition to alerting all
85 operators implied by the n key, dump interacts with the operator on
86 dump's control terminal at times when dump can no longer proceed, or if
87 something is grossly wrong. All questions dump poses must be answered
88 by typing “yes” or “no”, appropriately.
89 Since making a dump involves a lot of time and effort for full dumps,
91 dump checkpoints itself at the start of each tape volume. If writing
92 that volume fails for some reason, dump will, with operator permission,
93 restart itself from the checkpoint after the old tape has been rewound
94 and removed, and a new tape has been mounted.
95 Dump tells the operator what is going on at periodic intervals, includ‐
97 ing usually low estimates of the number of blocks to write, the number
98 of tapes it will take, the time to completion, and the time to the tape
99 change. The output is verbose, so that others know that the terminal
100 controlling dump is busy, and will be for some time.
101 Now a short suggestion on how to perform dumps. Start with a full
103 level 0 dump
104 dump 0un
106 Next, dumps of active file systems are taken on a daily basis, using a
108 modified Tower of Hanoi algorithm, with this sequence of dump levels:
109 3 2 5 4 7 6 9 8 9 9 ...
110 For the daily dumps, a set of 10 tapes per dumped file system is used
111 on a cyclical basis. Each week, a level 1 dump is taken, and the daily
112 Hanoi sequence repeats with 3. For weekly dumps, a set of 5 tapes per
113 dumped file system is used, also on a cyclical basis. Each month, a
114 level 0 dump is taken on a set of fresh tapes that is saved forever.
115
117 /dev/rxp0a default filesystem to dump from
118 /dev/rmt0 default tape unit to dump to
119 /etc/ddate old format dump date record (obsolete after -J option)
120 /etc/dumpdates new format dump date record
121 /etc/fstab Dump table: file systems and frequency
122 /etc/group to find group operator
123
125 restor(8), rdump(8), dump(5), fstab(5), dumpdir(8)
126
128 Many, and verbose.
129
131 Sizes are based on 1600 BPI blocked tape; the raw magtape device has to
132 be used to approach these densities. Fewer than 32 read errors on the
133 filesystem are ignored. Each reel requires a new process, so parent
134 processes for reels already written just hang around until the entire
135 tape is written.
136 It would be nice if dump knew about the dump sequence, kept track of
138 the tapes scribbled on, told the operator which tape to mount when, and
139 provided more assistance for the operator running restor.
1404th Berkeley Distribution DUMP(8)