NAME

dump − incremental file system dump

SYNOPSIS

dump [ key [ arguments ] file-system ]

DESCRIPTION

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

f Place the dump on the next argument file instead of the tape. 

u If the dump completes successfully, write the date of the beginning of the dump on file /etc/ddate.  This file records a separate date for each file system and each dump level. 

0−9 This number is the “dump level”.  All files modified since the last date stored in the file /etc/ddate for the same file system 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 file system to be dumped. 

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, the dump will wait for reels to be changed. The default size is 2,300 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 write. The default is 1600.

If no arguments are given, the key is assumed to be 9u and a default file system is dumped to the default tape. 

Now a short suggestion on how to perform dumps.  Start with a full level-0 dump: dump 0u.  Next, periodic level-9 dumps should be made on an exponential progression of tapes.  (Sometimes called Tower of Hanoi: 1, 2, 1, 3, 1, 2, 1, 4, ...; tape 1 used every other time, tape 2 is used every fourth, tape 3 is used every eighth, etc.): dump 9u.  When the level-9 incremental approaches a full tape (about 78,000 blocks at 1600 BPI blocked 20 blocks per record), a level-1 dump should be made: dump 1u.  After this, the exponential series should progress as if uninterrupted.  These level-9 dumps are based on the level-1 dump, which is based on the level-0 full dump.  This progression of levels of dumps can be carried as far as desired. 

FILES

default file system and tape vary with installation. 
/etc/ddate: record dump dates of file system/level.

SEE ALSO

cpio(1), restor(1M), volcopy(1M), dump(5). 

DIAGNOSTICS

If the dump requires more than one tape, it will ask you to change tapes.  Reply with a new-line after this has been done. 

BUGS

Sizes are based on 1600 BPI blocked tape.  The raw magnetic tape device has to be used to approach these densities.  Read errors on the file system are ignored.  Write errors on the magnetic tape are usually fatal. 

May 16, 1980  —  Obsolescent