About the node failure management
The following table lists the node failure scenarios and how they can be managed.
Table:
Node failure | Description |
|---|---|
Planned node failure | In a routine node maintenance, we recommend that you reduce the impact on deduplication ratio or a job failure. Set the node in a maintenance mode on an MVG server. The client policy assignments on the node are not automatically changed if the node is in maintenance mode. Run the following MSDP command to change them manually: cacontrol --mvg set-maintenance-mode <msdp-server> cacontrol --mvg unset-maintenance-mode <msdp-server> cacontrol --mvg get-maintenance-mode On the NetBackup web UI, go to the Disk Pool webpage of an MVG volume, select and edit a disk volume of an MVG volume, then switch the mode between "Maintenance" and "Normal". |
Unplanned node failure | The MVG server uses a rebalance freezing timeout to control when it reassigns disk volumes. If the default disk volume becomes unavailable, the MVG server will not select another volume for the same client-policy until the default volume remains unavailable beyond the configured timeout during the next backup. This setting is configurable using the tuning parameter asmt_rb_freezing_timeout through the MVG tuning API or the command line. See Specifications and default values of the MVG tuning parameters. |
The node is operational again after the failure | If a node stays down for long, the client policy assignments are moved out when NetBackup run backup jobs with the backup policies. When the node is back, most of the original client policy combinations are moved back to keep the system balanced again. |
The node is full | If a disk volume is full, a client policy is moved to another node. It is not moved back unless the new node becomes inactive or full and the original node has space available again. The setting can be disabled using the tuning parameter asmt_rb_freezing_on_disk_full through the MVG tuning API or the command line. See Specifications and default values of the MVG tuning parameters. |