Backups can be made in the units shown in Table 7-1. The unit is specified in an option of the database copy utility (pdcopy).

Table 7-1 Backup units

Backup unit	Explanation	pdcopy option specification
System	Makes a backup of all RDAREAs, including RDAREAs used by the system (such as the master directory RDAREA).	-a
Unit*	Makes a backup of a specified unit's RDAREAs.	-u unit-name
Server*	Makes a backup of a specified server's RDAREAs.	-s server-name
RDAREA	Makes a backup of a specified RDAREA.	-r RDAREA-name

^* Applicable to HiRDB/Parallel Servers.

A backup acquisition mode is specified in the -M option of the database copy utility (pdcopy). Table 7-2 lists the backup acquisition modes.

Table 7-2 Backup acquisition modes

Backup acquisition mode (-M option specification)	Explanation	Difference in RDAREA recovery depending on backup acquisition point
Referencing/updating-impossible mode (x)	While the backup is being made, RDAREAs being backed up cannot be referenced or updated. Before a backup, you must use the pdhold -c command to shut down and close the affected RDAREAs.	A backup made with this method can be used to recover the database to its status when the backup was made. In addition, by using system log information, you can recover the database to any synchronization point since the backup was made.
Referencing-permitted mode (r)	While the backup is being made, the RDAREAs being backed up can be referenced but not updated.
Updatable mode (s)1	While the backup is being made, the RDAREAs being backed up can be both referenced and updated.	The database cannot be recovered to its status when the backup was made, but it can be recovered to any synchronization point since the backup was made. Therefore, to recover the database, you need the backup and the system log information2 from a synchronization point subsequent to when the backup was made.

¹ A backup should not be made in the updatable mode during execution of a UAP (including a utility) that is running in the no-log mode or the pre-update log acquisition mode.

² The LAN IDs and generation numbers of the system log files required to recover the RDAREA are output to the process results output file of the database recovery utility.

A backup file can be created anywhere on a server machine on which HiRDB is running. A backup file need not be created on the server machine on which the RDAREAs are located. Devices such as CMT and DAT may not be available on the same server machine as the RDAREAs being backed up. The server machine on which a backup file is to be stored is specified in an option of the database copy utility (pdcopy).