On an M40e router with two host modules installed, determine whether the component you are removing belongs to the master host module. If it does, switch mastership to the other host module before removing the component. To check and switch host module mastership:
user@host> request chassis routing-engine master switch
The backup Routing Engine immediately assumes Routing Engine functions. If graceful switchover and nonstop routing are configured, packet forwarding and routing are continued without interruption. If the Routing Engines are configured for graceful switchover , but nonstop routing is not configured, there is no interruption to packet forwarding, but routing is interrupted momentarily. If neither graceful switchover nor nonstop routing is configured, packet forwarding halts while the backup Routing Engine becomes the master and the Packet Forwarding Engine components reset and connect to the new master Routing Engine. For information about configuring graceful switchover and nonstop routing, see the section about Routing Engine redundancy in the JUNOS System Basics Configuration Guide.
We recommend you run JUNOS Release 7.0 or later on the M10i router to support graceful switchover.
Note: Router performance might change if the backup Routing Engine's configuration differs from the former master's configuration. For the most predictable performance, configure the two Routing Engines identically, except for parameters unique to a Routing Engine, such as the hostname defined at the [edit system] hierarchy level and the management interface (fxp0 or equivalent) defined at the [edit interfaces] hierarchy level.
To configure Routing Engine-specific parameters and still use the same configuration on both Routing Engines, include the appropriate configuration statements under the re0 and re1 statements at the [edit groups] hierarchy level and use the apply-groups statement. For instructions, see the JUNOS System Basics Configuration Guide.