Cold-Restore Sequence on Extended Parallel Server

You must put the database server in microkernel mode to do a cold restore. If the database server or a coserver is offline, you cannot perform any restores. Figure 19 describes the ON–Bar cold-restore sequence.

In a cold restore, ON–Bar performs the following steps in order:

• Salvages the logical logs
• Merges the boot files
• Restores the root dbspace
• Restores the critical dbspaces
• Restores the other dbspaces
• Restores logical logs

The onbar-merger utility collects and processes the backup emergency boot files from each coserver to determine what restores are required. The onbar-merger then creates the restore boot file and copies it to each coserver that contains a backup emergency boot file.

You can specify in the bar_worker_coserver configuration parameter which coservers have boot files and run onbar-worker processes. For more information, see BAR_WORKER_COSVR (XPS).

For each storage space, ON–Bar restores the last level-0 backup, the level-1 backup (if it exists), and the level-2 backup (if it exists). Finally, it restores the logical logs.

Figure 19. ON-Bar Cold-Restore Sequence on Extended Parallel Server