DUMP(8)
NAME
dump − incremental file system dump
SYNTAX
/etc/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.
0−9 This number is the ‘dump level.’ All files are dumped that were 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.
B The next argument to dump is a number which specifies the size (in 1024-byte blocks) of a storage medium, such as a floppy diskette or removable disk cartridge. For example, the command
dump 9Bf 400 /dev/rra2a /dev/ra0a
can be used to dump to RX50 diskettes. The B key is needed when running restore to read this dump.
u If the dump completes successfully, writes 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 consists of one free format record per line: filesystem name, increment level and ctime(3) format dump date. You can edit /etc/dumpdates to change any of the fields.
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 waits for the reel to be changed. The default tape size is 2300 feet.
d The density of the tape, expressed in bits per inch, 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 taken 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 Unlike W, w prints only those filesystems which need to be dumped.
n Whenever dump requires operator attention, notify (by means similar to a wall(1) command) 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 more than 32). In addition to alerting all operators in the "operator" group, 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".
Because making a full dump involves a lot of time and effort, dump checkpoints itself at the start of each tape volume. If writing that volume fails for some reason, dump, with operator permission, restarts itself from the checkpoint after the old tape has been rewound and removed, and a new tape has been mounted.
Dump reports to the operator at periodic intervals, giving (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.
To perform dumps, start with a full level 0 dump
dump 0un
Next, take dumps of active file systems on a daily basis, with this sequence of dump levels:
3 2 5 4 7 6 9 8 9 9 ...
For the daily dumps, use a set of 10 tapes per dumped file system on a cyclical basis. Each week, take a level 1 dump is and the daily sequence repeats with level 3. For weekly dumps, use a set of five tapes per dumped file system on a cyclical basis. Each month, a level 0 dump is taken on a set of fresh tapes that is archived.
FILES
/dev/rrp1gdefault filesystem to dump from
/dev/rmt8default tape unit to dump to
/etc/ddateold format dump date record (obsolete after −J option)
/etc/dumpdatesnew format dump date record
/etc/fstabdump table: file systems and frequency
/etc/groupto find group operator
RESTRICTIONS
Sizes are based on 1600 BPI blocked tape; you must use the raw magnetic tape device to approach these densities. Anything 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.