Safe and limited modes in cluster safeguard critical provisioning errors for both standalone nodes and nodes in a cluster.
During provisioning operations such as configuring a map, in rare occasions there can be unrecoverable system errors that can potentially put the cluster or the clustered nodes or standalone nodes into unsafe or unstable states. Once in such a state, additional operations or configuration changes can cause the node to crash, the cluster to deform, or the data traffic to be impacted. For example, due to a node attempting to rejoin a cluster, a chassis can end up in a reboot loop. In previous software versions, there was no way to prevent entering the loop.
These modes provide notification, stop further operations from being performed, and give you time to troubleshoot and plan the recovery of the cluster or of any node in the cluster or standalone node.
Two modes are supported. The first is called safe mode and is triggered when the node detects unrecoverable errors, but the existing flow maps are not impacted. The second is called limited mode and is triggered when the node detects continuous system reboots. In this mode, the node will become standalone and only basic configuration will be allowed.
When a node enters safe mode it displays the following message when you attempt to make a change to the configuration that is not available in safe mode:
The system has restricted provisioning in safe mode. Contact Gigamon Support on how to troubleshoot and recover from safe mode.