Disabling Split and Merge in a Virtual Chassis
The split and merge feature is enabled by default on all EX Series switches and QFX Series devices in a Virtual Chassis. You can disable the split and merge feature. If you disable the split and merge feature and the Virtual Chassis splits, both parts of the split Virtual Chassis configuration remain active.
In a preprovisioned Virtual Chassis, if both of the Routing Engines end up in the same Virtual Chassis configuration after a split, the other part of the split Virtual Chassis configuration remains inactive. If the Routing Engines end up in different parts of the split Virtual Chassis configuration and the rest of the member switches are configured as having linecard roles, then a backup Routing Engine might not be selected for either part.
We recommend disabling split and merge on a Virtual Chassis with two member switches. A two-member switch Virtual Chassis that has disabled split and merge can reform more quickly and with less complications as a result of the feature being disabled.
To disable the split and merge feature in a Virtual Chassis:
user@switch# set virtual-chassis no-split-detection
To remove this configuration item to enable the split and merge feature again (recommended when a two-member Virtual Chassis is expanded to have more members):
user@switch# delete virtual-chassis no-split-detection