To speed up the restore process, you can import data backups from several data carriers simultaneously (group of parallel data carriers). Each data backup that consists of several data carriers can be restored sequentially or in parallel. Note though that you cannot restore log backups in parallel.
Restoring from a group of parallel data carriers is not fundamentally different from a sequential restore: During a sequential restore, you specify the backup template at the start of the operation. When the data is imported from the data carrier, the system asks you to enter the next backup template or an operating system path (including the name) where the next data carrier can be accessed. A parallel restore runs similarly to this, but takes place on several data carriers simultaneously. The system requests a new data carrier for the first data carrier that is completely imported, and proceeds accordingly for each individual data carrier until the data is completely imported. Therefore, a parallel restore is normally a combination of parallel and sequential restore operations that takes place when the number of data carriers to be imported exceeds the number of parallel data carriers.
You create a parallel backup on a group of 5 tape devices. This backup consists of 7 tapes. You can restore these 7 tapes in any order and parallelism.
If the system requests that you insert of a succeeding data carrier (message number -8020), then you must acknowledge this in order for the restore process to continue.
Even when you import all backup data carriers simultaneously, you may be asked by the system to insert a succeeding data carrier. This is because the number of data carriers used for the backup is stored on the last data carrier to finish during the backup operation only. If the system first finishes the import of a data carrier that does not contain this information, the system asks you to enter the next data carrier.
You can acknowledge this as follows:
Enter the next data carrier.
Enter the command to only import data from the other data carriers.
If Database Manager CLI is used, then you can also enter the AUTOIGNORE option at the start of the restore procedure. This allows the system to import data from the other data carriers only. You can simplify background restore operations in this way.
Only use this option when you are sure that the complete amount of data to be restored can be imported in parallel. This means that the technical specifications allow all backup data carriers to import data simultaneously.
The data backup to be imported in parallel consists of several data carriers.
If you have created the backup using a third-party backup tool, the following prerequisites must also be met:
You must use the same backup tool for a restore that was used for the backup.
The number of group parallel data carriers for a restore must be exactly the same as the number of data carriers used for creating the backup.
Note that if a deadlock occurs during the parallel recovery of the database using a backup tool, you have to import the data carriers in the group one after the other.
Use the normal functions for restoring data.
More information: Restoring Databases
Data backup/s successfully imported. If the database has to be restored due to a hardware defect or a logical error, you may have to import log backups to restore the database to a consistent state.