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Procedure documentationPreparing for a Full-System Cold Restore (ON-Bar)  Locate the document in its SAP Library structure

Use

This section tells you what to do before performing a full-system cold restore of your Informix database if you use ON-Bar as your data recovery tool (that is, for your database and logical-log backups).

Note

To make a restore easier, label your tapes after every database or logical-log backup. Include all essential information required for a restore, such as date of backup, save set id, volume set and volume, dbspace names, logical-log file numbers, and so on. Your storage manager – for example, Informix Storage Manager (ISM) – normally requests the correct storage media for each stage of the restore.

Procedure

  1. Decide which database backup to use for the restore. By default, ON-Bar derives the most recent backup from the entry in the ON-Bar emergency boot file and uses this backup for the restore.
  2. Decide if you want to restore to a "Point-in-Time" (PIT) or a "Point-in-Log" (PIL) during the logical restore phase. This depends on when the error occurred. Refer to Identifying the Problem Requiring a Restore.
  3. Make sure that the storage media containing your chosen level-0, level-1, and level-2 database backups are available to your storage manager, which requests storage media as required during the restore.

    4. You need to gather the best set of storage media possible for the restore. You need at least a full set of storage media from a level-0 backup. Use the storage media from a level-1 and level-2 backup if available, since they speed up the restore (that is, the restore runs more quickly than when you use the logical-log backup storage media instead).

  4. Make sure that the storage media containing the logical-log backups are available to your storage manager, which requests storage media as required during the restore.

    5. You need the storage media containing logical-log backups corresponding to the database backup from the previous step. How you proceed depends on what kind of database backup you are using to restore:

    · Whole-system backup

    Make sure that the logical-log backups are available dating from the latest database backup of all dbspaces that you intend to use for the restore. The latest database backup can be at any level, but you must start with a level-0 backup.

    · Storage-space backup

    Make sure that the logical-log backups are available dating from the beginning of the first database backup that you intend to use for the restore. These backups are needed to synchronize the different components of the storage-space backup.

    Note

    For faster performance in a restore, assign separate storage devices for backing up storage spaces and logical logs. If physical and logical backups are mixed together on the storage devices, it takes longer to scan the tape during a restore.

  5. Verify your database server and storage manager configuration.

    6. Make sure that the current database server configuration is compatible with, and accommodates, all ONCONFIG parameter values assigned after the backup that you intend to use. Use the copy of this file that was in use at the time of the backup.

    All raw devices or files that have been used since the level-0 backup must be available. Changes can include, for example, chunks added, dbspaces dropped, dbspaces mirrored, and so on.

  6. Make sure that you have the following database configuration files dating from the backup that you intend to use for the restore:

· The ON-Bar emergency boot file (that is, the ixbar file)

· The server boot file (that is, the oncfg file)

· The sqlhost file (UNIX only)

· The ONCONFIG file

· Storage manager files

These files are normally stored in the directory $INFORMIXDIR/etc (UNIX) or %INFORMIXDIR%\etc (NT). For more information, see Configuring ON-Bar.
  1. Decide whether you want to perform a restartable restore.

A restartable restore is slower but lets you restart the restore midway through if you need to (for example, if there is a failure). You have to decide whether the restore is restartable before you start.

To allow a restore to be restarted, set the RESTARTABLE_RESTORE parameter to ON in the ONCONFIG file as follows before you start the restore. To check the setting of this parameter in the ONCONFIG file, see Listing System Information with SAPDBA. The default is OFF (that is, restart is not possible).

Result

Now you can go on to Salvaging Logical Logs for a Full-System Cold Restore (ON-Bar).

 

See also:

Informix documentation