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AIX Version 4.3 Commands Reference, Volume 4

rdump Command


Backs up files onto a remote machine's device.

Note: User must have root authority to run this command.


rdump [ -b Blocks ] [ -B ] [ -c ] [ -d Density ] [ -L Length ] [ -s Size ] [ -u ] [ -w ] [ -W ] [ -Level ] -f Machine:Device [ FileSystem | DeviceName ]


The rdump command copies file systems by i-node from your local machine to a remote machine. The files are copied, using the backup command format, to a device on the remote machine. The device is accessed by using a remote server on the remote machine. You must have root authority to execute the rdump command. You must also define a local machine running the rdump command in the /.rhosts file of the target remote machine.

To back up a file system, specify the -Level and FileSystem parameters to indicate the files you want to back up. You can use the -Level parameter to back up either all files on the system (a full backup) or only the files that have been modified since a specific full backup (an incremental backup). The possible levels are 0 to 9. If you do not supply a level, the default level is 9. A level 0 backup includes all files on the file system. A level n backup includes all files modified since the last level n - 1 ( n minus 1) backup. The levels, in conjunction with the -u flag, provide a method of maintaining a hierarchy of incremental backups for each file system.

  1. Use the -u flag when you perform an incremental backup (the -Level parameter) to ensure that information regarding the last date, time, and level of each incremental backup is written to the /etc/dumpdates file.
  2. If the rmt command on the remote machine is not in /usr/sbin/rmt, then a link will need to be created on the remote machine from /usr/sbin/rmt to its actual location (usually /etc/rmt).


-b Blocks Specifies the number of blocks to write in a single output operation. If you do not specify the Blocks variable, the rdump command uses a default value appropriate for the physical device selected. Larger values of the Blocks variable result in larger physical transfers to tape devices.
-B Terminates the command without querying the user when an error occurs. If you specify the -B flag, the rdump command returns a nonzero value.
-c Specifies that the tape is a cartridge format, not a 9-track format.
-d Density Specifies the density of the tape in bits-per-inch (bpi). This value is used in calculating the amount of tape used per volume. If you do not specify a value for the Density variable, the default density is 1600 bpi. When using the -c flag without specifying a tape density, the default density is 8000 bpi.
-f Machine:Device Specifies the Machine variable as the hostname of the remote machine. To send output to the named device, specify the Device variable as a file name (such as the /dev/rmt0 file). The Device variable should specify only tape devices.
-L Length Specifies the length of the tape in bytes. This flag overrides the -c, -d, and -s flags. You can specify the size with a suffix of b, k, m, or g to represent Blocks (512 bytes), Kilo (1024 bytes), Mega (1024 Kilobytes), or Giga (1024 Megabytes), respectively. To represent a tape length of 2 Gigabytes, enter -L 2g. This flag only applies to AIX Version 4.2 and above.
-s Size Specifies the size of the tape in feet using the Size variable. If you do not specify a tape size, the default size is 2300 feet. When using the -c flag without specifying a tape size, the default size is 1700 feet. When the tape drive reaches the specified size, the rdump command waits for the tape to be changed.
-u Updates the time, date, and level of the remote backup in the /etc/dumpdates file. This file provides the information needed for maintaining incremental backups.
-w Currently disabled.
-W Displays the file systems found in the /etc/dumpdates files.
-Level Specifies the remote backup level (0 to 9). The default value of the Level variable is 9.
-? Displays the usage message.


DeviceName Specifies the physical device name (the block or raw name).
FileSystem Specifies the name of the directory on which the file system is normally mounted. The rdump command reads the /etc/filesystems file for the physical device name. If you do not specify a file system, the default is the root (/) file system.

Exit Status

This command returns the following exit values:

0 Indicates that the command completed successfully.
>0 Indicates that an error occurred.


  1. To back up files in the /usr directory on your local machine to a remote machine, enter:
    rdump -u -0 -fcanine:/dev/rmt0 /usr
    The -u flag tells the system to update the current backup level records in the /etc/dumpdates file. The -Level flag set to backup level 0 specifies that all the files in the /usr directory are to be backed up. The ID of the remote machine is canine and the device is the /dev/rmt0 device.
  2. To back up files in the /usr directory on your local machine to a remote machine using an 8mm, 2.3GB tape, enter:
    rdump -fcanine:/dev/rmt0 -L 2200m /usr
    Note: 2.2GB is used here instead of 2.3GB to avoid hitting the actual end of the tape.
  3. To back up files in the /usr directory on your local machine to a remote machine using 0.25-inch tape, enter:
    rdump -fcanine:/dev/rmt0 -c /usr
    When using the -c flag, the rdump command defaults to the correct size and density values for 0.25-inch tape.


/etc/dumpdates Contains logs of the most recent remote dump dates.
/etc/filesystems Contains information on file systems.
/dev/rhd4 Contains the device where the default file system (root) is located.
/usr/sbin/rdump Contains the rdump command.

Related Information

The find command, dd command, backup command, restore command, rrestore command.

The dumpdates file, filesystems file, rmt special file.

Backup Overview for System Management, Directory Overview, Files Overview, File Systems Overview for System Management in AIX Version 4.3 System User's Guide: Operating System and Devices.

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