Owner's Manual

66 | Chapter 3. Managing the Switch
NETGEAR 8800 User Manual
You can cause the primary to failover to the backup, thereby relinquishing its primary status.
To cause the failover:
1. Use the show switch {detail} command on the primary or the backup node to confirm
that the nodes are synchronized and have identical software and switch configurations
before failover. The output displays the status of the nodes, with the primary node
showing
MASTER and the backup node showing BACKUP (InSync).
A node may not be synchronized because checkpointing did not occur, incompatible
software is running on the primary and backup, or the backup is down.
• If the nodes are not synchronized and both nodes are running a version of XCM8800
that supports synchronization, proceed to
step 2.
• If the nodes are synchronized, proceed to step 3.
2. If the nodes are not synchronized because of incompatible software, use the synchronize
command to ensure that the backup has the same software in flash as the primary.
The synchronize command:
• Reboots the backup node to prepare it for synchronizing with the primary node
• Copies both the primary and secondary software images
• Copies both the primary and secondary configurations
• Reboots the backup node after replication is complete
After you confirm the nodes are synchronized, proceed to step 3.
3. If the nodes are synchronized, use the run failover {force} command to initiate failover
from the primary node to the backup node. The backup node then becomes the primary
node and the original primary node reboots.
Replicating Data Between Nodes
XCM8800 replicates configuration and run-time information between the primary node and
the backup node so that the system can recover if the primary fails. This method of
replicating data is known as checkpointing. Checkpointing is the process of automatically
copying the active state from the primary to the backup, which allows for state recovery if the
primary fails.
Replicating data consists of the following three steps:
1. Configuration synchronization—Relays current and saved configuration information from
the primary to the backup
2. Bulk checkpoint—Ensures that each individual application running on the system is
synchronized with the backup
3. Dynamic checkpoint—Checkpoints any new state changes from the primary to the backup
To monitor the checkpointing status, use the show checkpoint-data {<process>} command.
Data is not replicated from the primary to the standby nodes.