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dump File system backup.
dump [-0123456789cnua] [-B <records>] [-b <blocksize>] [-d <density>]
[-f <file>] [-h <level>] [-s <feet>] [-T <date>] <filesystem>

dump [-W || -w]

(The 4.3BSD option syntax is implemented for backward compatibility, but is not documented.)
dump examines files on a file system and determines which files need to be backed up. These files are copied to the given disk, tape, or other storage medium for safekeeping. 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 each volume is of a fixed size; the actual size is determined by the tape size and density and/or block count options. By default, the same output filename is used for each volume after prompting the operator to change media.
-0-9 Dump levels. A level 0, full backup, guarantees the entire file system is copied. A level number above 0, an incremental backup, tells dump to copy all files new or modified since the last dump of the same or lower level. The default level is 9.
-c Changes the defaults for use with a cartridge tape drive, with a density of 8000 bpi and a length of 1700 feet.
-n Notifies all operators in the operator group whenever dump requires operator attention.
-u Updates the file /etc/dumpdates after a successful dump. The format of /etc/dumpdates is readable by people, consisting of one free format record per line: file system name, increment level, and ctime (3). There may be only one entry per file system at each level.
-B <records> The number of kilobytes per volume, rounded down to a multiple of the block size. This option overrides the calculation of the tape size.
-b <blocksize> The number of kilobytes per dump record. Because the IO system slices all requests into chunks of MAXBSIZE (typically 64KB), it is not possible to use a larger block size without having problems later with restore. Therefore, dump constrains writes to MAXBSIZE.
-d <density> Sets the tape density to <density>. The default is 1600 bpi.
-f <file> Writes the backup to <file>. <file> may be a special device file, such as a tape drive or disk drive, an ordinary file, or - (standard output). Multiple filenames 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 listed, the last filename will be 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, dump writes to the named file on the remote host using rmt.
-h <level> Honors the user nodump flag only for dumps at or above the given <level>. The default honor level is 1, so that incremental backups omit such files but full backups retain them.
-s <feet> Attempts to calculate the amount of tape needed at a particular density. If this amount is exceeded, dump prompts for a new tape. It is recommended to be a bit conservative on this option. The default tape length is 2300 feet.
-T <date> Uses the specified date as the starting time for the dump instead of the time determined from looking in /etc/dumpdates. The format of the date is the same as that of ctime (3). This option is useful for automated dump scripts that wish to dump over a specified period of time. The -T flag is mutually exclusive from the -u flag.
-W Tells the operator what file systems need to be dumped. The information is gleaned from /etc/dumpdates and /etc/fstab. The -W flag causes dump to print out, for each file system in /etc/dumpdates the most recent dump date and level, and highlights of those file systems that should be dumped. If the -W flag is set, all other options are ignored, and dump exits immediately.
-w Is like W, but prints only those file systems that need to be dumped.
dump 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 flag, dump interacts with an 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 dump involves a lot of time and effort for full dumps, dump checkpoints itself at the start of each tape volume. If writing that volume fails for some reason, dump 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.
dump 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.



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