JunOS : Versions running on dual partitions are not same

By | April 13, 2018

Having the following notification on the console output after booting your Juniper EX switch?

WARNING: JUNOS versions running on dual partitions are not same

This might have been caused by an incomplete/failed upgrade of JunOS. Either way, unless this is the result of an action made on purpose, it is important that both slices have the same mirrored content.

To resolve this issue, make sure you are currently booted on the slice with the version you want to run into production. To find out, run the following command :

You will have an output similar to this :

As we can see, we are currently running on the secondary slice (/dev/da0s2a), running v15.1R6.7. The primary slice (/dev/da0s1a) is out of sync.

In that case, the healthy slice (/dev/da0s2a) and version we want to run into production is 15.1R6.7, we will replicate to the primary slice (/dev/da0s1a) using the builtin JunOS snapshot mechanism. In order to do that, we will use the following command :

NOTICE : This will format the slice marked as “backup” and copy the slice marked as “primary” to it.

This will take a little while, and system might become unstable under certain conditions. Here is the output following that command :

This should take less than 10 minutes. Once done, validate once again both slices with this command :

show system snapshot media internal

Then it should look like :