Restarting After Critical Data Is Damaged

If one of the database servers experiences a failure that damages the root dbspace, the dbspace that contains logical-log files, or the dbspace that contains the physical log, you must treat the failed database server as if it has no data on the disks, and you are starting HDR for the first time. Use the functioning database server with the intact disks as the database server with the data.

Critical Media Failure on the Primary Database Server

You might need to restart HDR after the primary database server suffers a critical media failure. Table 46 lists the commands required to perform this procedure.

To restart HDR after a critical media failure

If the original secondary database server was changed to a standard database server, bring this database server (DRAUTO = 0) to quiescent mode and then use the onmode -d command to change the type back to secondary.
If DRAUTO = 1 (RETAIN_TYPE), this step does not apply. The database server automatically performs a graceful shutdown and switches back to type secondary when you bring the primary database server back online.

If DRAUTO = 2 (REVERSE_TYPE), the secondary database server becomes a primary database server as soon as the connection ends when the old primary server fails, rather than when the old primary server is restarted.
Restore the primary database server from the last dbspace backup.
Use the onmode -d command to set the type of the primary database server and to start HDR.
The onmode -d command starts a logical recovery of the primary database server from the logical-log files on the secondary database server disk. If logical recovery cannot complete because you backed up and freed logical-log files on the original secondary database server, HDR does not start until you perform step 4.

Apply the logical-log files from the secondary database server, which were backed up to tape, to the primary database server.

If this step is required, the primary database server sends a message prompting you to recover the logical-log files from tape. This message appears in the message log. When all the required logical-log files have been recovered from tape, any remaining logical-log files on the secondary disk are recovered.

Table 46. Steps for Restarting HDR After a Critical Media Failure on the Primary Database Server
Step	On the Primary Database Server	On the Secondary Database Server
1.		onmode command onmode -s onmode -d secondary `prim_name`
2.	ON–Bar command onbar -r -p ontape command ontape -p
3.	onmode command onmode -d primary `sec_name`
4.	ontape command ontape -l

Critical Media Failure on the Secondary Database Server

If the secondary database server suffers a critical media failure, you can follow the same steps listed under Starting HDR for the First Time.

Critical Media Failure on Both Database Servers

In the unfortunate event that both of the computers that are running database servers in a replication pair experience a failure that damages the root dbspace, the dbspaces that contain logical-log files or the physical log, you need to restart HDR.

To restart HDR after a critical media failure on both database servers

Restore the primary database server from the storage space and logical-log backup.
After you restore the primary database server, treat the other failed database server as if it had no data on the disks and you were starting HDR for the first time.
(See Starting HDR for the First Time.) Use the functioning database server with the intact disks as the database server with the data.