Typically, backup options are defined once, then multiple backup jobs are run using the same options. To make identical backup jobs unique, the Teradata Access Module for Tivoli tags each storage object with a unique generation number that is assigned when ARCMAIN starts the File Open function. View these numbers by using the %gen% format field in TDDSMC QUERY BACKUP and QUERY OBJECT commands.
By default, a request for a backup produces only the most recently created file generation (latest), or the active version in Tivoli terms. All other copies of a relevant object in storage are referred to by Tivoli as inactive versions. The generation parameter is not needed when requesting a restore of the latest (active) backup generation. However, when restoring an inactive backup, use the GENERATION field of the IOPARM string.
Generation numbers are not part of the file name or the TSM naming convention. Instead, the Teradata Access Module for Tivoli stores the generation number inside the TSM object information. To ensure the creation of unique generation numbers for concurrent backups that use the same name, object segment zero (F0000) acts as a placeholder for the job-specific generation number. Object segment zero contains no data and is constructed and committed in its own TSM transaction.