DB2 Server for VSE & VM: Data Restore Guide

User Archives

There are many ways to perform a backup depending on the operating system and on the programs installed in this environment.

An archive taken using non-DB2 facilities is called a user archive. It can only be performed offline, that is when the database manager has been shut down by SQLEND UARCHIVE. Never use SQLEND or SQLEND QUICK when performing a user archive. You must use SQLEND UARCHIVE, because this:

• Creates an entry in the log history area.
• Makes a checkpoint, and thus leaves the database in a clean status for the archive.
• Avoids unnecessary UNDO/REDO operations after restoring the database from a user archive.

User archives let you use a variety of tools and you can switch between different types of archive as often as you like. The following is a list of non-DB2 archive tools available:

• DDR

  Available on VM only. It can be executed in VM as a module or from a standalone tape to back up either a VM minidisk or a DASD belonging to VSE.

  The disadvantage of DDR is that it requires some input definitions to be supplied and these must be maintained in case the physical layout of the database changes.

  In VM this means, that the procedure that initiates the copy needs to know about all the minidisks belonging to the database. Use the current directory file, for example USER DIRECT, or the SQLFDEF file that is maintained by the database manager and is available on the DB2 production disk.

  In VSE, only complete disks, not dbextents, can be copied, and VSAM definitions on those disks must not be changed.

• DFSMS^(TM)

  Available on VM only.

  It performs better than DDR in most cases but, as DDR, it requires that you supply input definitions and maintain them in case the physical layout of the database changes.

• VSAM IDCAMS Backup/Restore

  Available on VSE only. IDCAMS BACKUP can be applied. As with DDR and DFSMS, VSAM Backup/Restore requires some input parameters related to the extents and must be maintained if the design of the database changes. For a detailed description of this command see the IBM VSE/VSAM Commands manual.

  The VSAM IDCAMS REPRO command cannot be used for the backup of DB2 extents.

• Any other user or vendor written application that can perform any type of backup of complete disks or minidisks. Most of these backup applications are based on DDR in VM for the copy of a whole minidisk.

Restore is made using the same tool as the archive, and then restarting the database with STARTUP=U for forward log recovery.

Note:

Typically, no table level recovery is available using these user archive tools.