scdhold [-d][-o] {TAM-file-name file-name|-s TAM-file-name}

The tambkup command backs up the contents of a specified TAM file into a specified file or standard output.

The contents backed up from the TAM file can be restored with the tamrstr command.

The tambkup command also outputs the specified TAM file record to the specified file in the form of a TAM data file.

-d

Creates a TAM data file from effective records in a TAM file. The TAM data file is to store data sorted in ascending order on the basis of a key value.

The tambkup command with its -d option specified must be executed when online operation terminates normally or after executing the tamhold and tamrm commands.

An error occurs if there is no effective record in the TAM file.

An error also occurs if broken records in the TAM file are detected.

-o

Backs up a TAM file in online mode.

This option is valid only when the TAM file is in the online mode.

If the option is not specified, the TAM file is to be backed up in the offline mode. The offline mode backup procedure is as follows:

1. Execute the tamhold command to logically shut down the TAM table.
2. Execute the tamrm command to remove the logically shutdown TAM table from the online system.
3. Execute the tambkup command with its -o option not specified to backup the TAM file.

-s

This option must be specified to output the backup to the standard output.

The -d and -o options are mutually exclusive.

TAM-file-name~<path name>

Specifies the name of the backup source TAM file, expressed as the full path name.

file-name~<path name>

Specifies the name of the backup destination file.

Specifies the name of the TAM data file when the -d option is specified.

This command argument cannot be specified with the -s option.

• When the tambkup command with its -d option specified is executed to exchange the contents of a TAM file, the user must ensure matching in journal generation number. If an attempt is made to recover the TAM file (execute the tamfrc command) or restart the online system with generation mismatching, system operation is not guaranteed.
• The information stored in a TAM file before exchange is not reflected in the file at online restart if:
  The user executes the tambkup command with its -d option specified for a TAM file that was removed from the online system with the tamhold and tamrm commands, thereby exchanging the contents of the TAM file and then executes the tamadd command to add and catalog the file to the online system.
  
• The tambkup command with its -o option not specified cannot be used for a TAM file being used online.
• Once online backup is completed, a message (KFCA01738-I) is output. This message is usually output to the standard output, but output to the standard error output when the -s option is specified. The message contains the generation number and block number of journal files to be recovered. Recovery of a TAM file requires the unloaded-journals file starting with the generation number and block number.
• The memory requirement for the tambkup command depends on the size of the TAM file to be backed up. Use the following formula to estimate the memory requirement (in bytes):
  400000 + A + B
  

  Legend:

  A: record-count x record-length. Add the value of A only when the -d option is specified.

  B: Size of the target TAM file. For the formula for estimating TAM file size, see H.7 Estimating the size of a TAM file.