The bak dump command is used to perform a dump operation. When you enter the command, specify the fileset family to be dumped and the level at which the family is to be dumped. All entries in the specified fileset family are dumped according to the dump level that you specify. If you specify a full dump level, all of the data in all of the filesets included in the specified family is dumped; if you specify an incremental dump, only the data in the filesets that has changed since the filesets were dumped at the parent of the dump level that you specify is dumped.
The fileset family and dump level that you specify produce a dump set. To indicate the contents of the dump set, the dump set name consists of the fileset family name joined by a period to the last component of the name of the dump level at which the family was dumped. For example, if the fileset family named usersys is dumped at the /weekly/monday level, the name of the resulting dump set is usersys.monday.
The Backup System overwrites a tape that contains an existing dump set only if both of the following conditions are true:
· The tape's label contains an acceptable name. An acceptable name is one that matches the name of the dump set you want to dump to the tape, in the form fileset_family_name.dump_level.index. Note that a tape's index is its position in the sequence of tapes necessary to accommodate the dump set; for example, the first tape for a dump set has an index of 1. A tape that is labeled as empty or that has no label is also acceptable.
· The tape's expiration date, if it exists, has expired. The Backup System refuses to overwrite a tape whose expiration date has not expired. Once a tape's expiration date has expired, the Backup System overwrites the contents of the tape with a dump set that has an acceptable name.
Use the bak labeltape command to overwrite a label that has an unacceptable name or an unexpired expiration date. Overwriting a tape's label removes all obstacles that can prevent it from being overwritten.
Note: If a dump operation is interrupted or fails for any reason, you cannot be sure that any fileset is complete on one tape; the Backup Database contains an entry for the incomplete dump set, which cannot be used to restore data. Immediately restart the backup, using the same tape to record the dump set; using the same tape automatically removes the entry for the incomplete dump set from the Backup Database. If you use a different tape, you will need to use the bak deletedump command to manually remove the entry for the incomplete dump set from the database. (See Deleting Backup Information for more information about the bak deletedump command.)
More:
Using Tapes with a Backup Operation
Backing Up a Fileset (Creating a Dump Set)