HP StoreOnce Backup System Concepts and Configuration Guidelines (BB877-90913, November 2013)

Failover support with backup applications
Backup applications do not have an awareness of advanced features such as autonomic failover
because they are designed for use with physical tape libraries and NAS storage. From the
perspective of the backup application, when failover occurs, the virtual tape libraries and the NAS
shares on the HP B6200 Backup System go offline and after a period of time they come back
online again. This is similar to a scenario where the backup device has been powered off and
powered on again.
Each backup application deals with backup devices going offline differently. In some cases, once
a backup device goes offline the backup application will keep retrying until the target backup
device comes back online and the backup job can be completed. In other cases, once a backup
device goes offline it must be brought back online again manually within the backup application
before it can be used to retry the failed backups.
In this section we shall briefly describe three popular backup applications and their integration
with the autonomic failover feature. Information for additional backup applications will be published
on the B6200 support documentation pages when it is available.
• HP Data Protector 6.21: job retries are currently supported by using a post-exec script.
Download from B6200 support documentation.
• Symantec NetBackup 7.x: job retries are automatic, but after a period without a response
from the backup device the software marks the devices as “down”. Once failover has completed
and the backup device is responding again the software does not automatically mark the
device as “up” again. A script is available from HP that continually checks Symantec device
status and ensures that backup devices are marked as “up”. With this script deployed on the
NetBackup media server, the HP B6200 Backup System failover works seamlessly. Download
from B6200 support documentation. NetBackup can go back to the last checkpoint and carry
on from there, if checkpointing has been enabled in the backup job. So, all the data backed
up prior to failover is preserved and the job does not have to go right back to the beginning
and start again.
• EMC Networker 7.x:
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VTL: Job retries are automatically enabled for scheduled backup jobs. No additional scripts
or configuration are required in order to achieve seamless integration with the HP B6200
Backup System. In the event of a failover scenario, the backup jobs are automatically retried
once the HP B6200 Backup System has completed the failover process. EMC Networker also
has a checkpoint facility that can be enabled. This allows failed backup jobs to be restarted
from the most recent checkpoint.
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NAS: The combination of Networker and NAS is not supported with autonomic failover and
use could cause irrecoverable data loss.
It is strongly recommended that all backup jobs to all nodes be configured to restart (if any action
to do this is required) because there is no guarantee which nodes are more likely to fail than others.
It is best to cover all eventualities by ensuring all backups to all nodes have restart capability
enabled, if required.
Whilst the failover process is autonomic, the failback process is manual because the replacement
or repaired node must be brought back on line before failback can happen. Failback can be
implemented either from the CLI or the GUI interface.
Restores are generally a manual process and restore jobs are typically not automatically retried
because they are rarely scheduled.
48 Configuring FC to support failover in a StoreOnce B6200 Backup system environment