A Backup Database machine houses the Backup Database. As with Fileset Database machines, it is best to configure three or a larger, odd number of Backup Database machines sufficient to back up the cell's data.
Each Backup Database machine runs the following processes:
· A Backup Server (bakserver process).
· Two upclient processes: one to retrieve configuration files from the System Control machine, and one to retrieve binary files from the Binary Distribution machine of the proper CPU/OS type.
· A BOS Server (bosserver process). (See Choosing DFS Machine Roles for more information about the BOS Server.)
A Backup Database machine stores the Backup Database. The Backup Database houses administrative information used in the DFS Backup System, such as the dump schedule for backups and the groups of filesets to be dumped to tape in each backup. The information in the database can be used to restore data from tape to the file system in the event of a system failure. There is one master copy of the Backup Database per cell.
The Backup Server, or bakserver process, maintains the Backup Database. The bakserver process must run on all machines that store a copy of the Backup Database. The admin.bak list is used to designate administrative users who can issue commands in the bak suite, most of which communicate with the Backup Server. The same admin.bak list should be used for all Backup Servers in a cell.
Commands in the bak suite are used to communicate with the DFS Backup System. They can be entered from any machine in the cell. Data is physically backed up and restored on a Tape Coordinator machine, which is a client or server machine that has a tape drive and runs the butc process to manage the drive. Information stored in the Backup Database determines the data to be backed up by a Tape Coordinator machine. (See Configuring the Backup System for more information on configuring and using Tape Coordinator machines.)