6.1.1 Basics

Organization of this subsection
(1) Backup unit
(2) Backup timing
(3) Server machine to be used to store a backup file
(4) Backing up RDAREAs without using the database copy utility
(5) List RDAREAs
(6) Creating a backup file in a character special file
(7) Backup file size (important)
(8) Checking a backup file's contents
(9) Note

(1) Backup unit

The backup unit is specified in an option of the database copy utility. Data can be backed up in the following units:

* Function applicable to HiRDB/Parallel Servers only.

(2) Backup timing

Data should be backed up daily. If this is not possible, data should be backed up at the following times:

  1. Before and after executing the database load utility or database reorganization utility in the no-log mode or the pre-update log acquisition mode
  2. After executing the database structure modification utility
  3. Before and after executing the dictionary import/export utility (before and after importing table definition information or stored procedures)
  4. After executing the optimizing information collection utility
  5. After recovering RDAREAs with the database recovery utility (applicable when an unload log or system log information is used as the input information)
  6. After executing a definition SQL or the PURGE TABLE statement
  7. After updating a large amount of table data
  8. After registering a plug-in (after executing the pdplgrgst command)
  9. When utilization of a plug-in is disabled (after the pdplugin operand is deleted from the system common definition)
  10. Before installing a new version of HiRDB*
  11. Before and after executing a UAP in the no-log mode (PDDBLOG=NO)
* The following RDAREAs should be backed up:
  • Master directory RDAREA
  • Data directory RDAREA
  • Data dictionary RDAREAs

(3) Server machine to be used to store a backup file

A backup file can be created in any server machine on which HiRDB is running. There is no requirement that a backup file be created in the same server machine where the RDAREAs being backed up are located. A server machine containing a device such as CMT or DAT may be used.

The server machine to be used to store a backup file can be specified in an option of the database copy utility (pdcopy command).

(4) Backing up RDAREAs without using the database copy utility

When an RDAREA is backed up without using the database copy utility, the following must be completed before the backup operation is started:

(5) List RDAREAs

List RDAREAs cannot be backed up. There is no need to make such backups, because lists can be re-created easily as long as the tables used for the lists are available.

(6) Creating a backup file in a character special file

If a character special file is used for a backup file, the character special file must be placed in a HiRDB file system area for utilities. To do this, UTL must be specified in the -k option of the pdfmkfs command.

(7) Backup file size (important)

If a message reporting a disk space shortage is output during execution of the database copy utility even though ample disk space has been provided, the following are possible causes:

In such a case, specify use of large files or change the kernel parameter value. You can also avoid the problem by creating multiple backup files. However, if the OS does not support large files, you must keep the disk partition size to 2 GB or smaller to be able to handle multiple files.

(8) Checking a backup file's contents

You can use the pdbkupls command to check the backup information collected by the database copy utility. For example, you can check the information listed below (for details about the information that can be checked, see the manual HiRDB Version 8 Command Reference):

(9) Note

Do not restore from backup information collected by the database copy utility on another HiRDB. For the method of migrating data to another HiRDB, see 12.1 Migrating a table to another HiRDB system.