dump

Used to back up ext2 or ext3 file systems

Supplementary instructions

dump command is used to backup ext2 or ext3 file system. Directories or entire file systems can be backed up to a specified device, or to a large file.

grammar

dump(option)(parameter)

Options

-0123456789: Backup level;
-b<block size>: Specify the block size in KB;
-B<Number of blocks>: Specifies the number of blocks in the backup volume;
-c: Modify the default density and capacity of the backup tape;
-d<density>: Set the density of the tape. The unit is BPI;
-f<device name>: Specify the backup device;
-h<level>: When the backup level is equal to or greater than the specified level, files marked as "nodump" by the user will not be backed up;
-n: When the backup job requires administrator intervention, send a notification to all users in the "operator" group;
-s<tape length>: the length of the backup tape, in feet;
-T<date>: Specify the time and date of backup;
-u: After the backup is completed, record the backup file system, level, date and time in /etc/dumpdates;
-w: Similar to -W, but only displays files that need to be backed up;
-W: Display the files that need to be backed up and the level, time and date of their last backup.

Parameters

Backup source: Specify the files, directories or file systems to be backed up.

Example

Back up all the contents of the /home directory to the /tmp/homeback.bak file. The backup level is 0 and record relevant information in /etc/dumpdates:

‍dump -0u -f /tmp/homeback.bak /home

Back up all the contents of the /home directory to the /tmp/homeback.bak file. The backup level is 1 (only the data that has changed since the last backup using level 0 is backed up) and in /etc Record relevant information in /dumpdates:

dump -1u -f /tmp/homeback.bak /home

Through the backup level of the dump command, full + incremental backup, full + differential backup can be achieved, and unattended backup can be achieved with crontab.