Hello Stephan,
the legacy devices like EX3200, EX3300, EX4200 have internal flash hardware which are very susceptible to power outages and other things which affect the internal flash memory (like writing log messages). For these devices, depending on your config and usage, it is indeed often the cleanest method for an upgrade.
Nowadays this has changed a bit, most modern devices have better internal SSDs which are not that susceptible to the above mentioned issues. However, if there are 30 power outages, then it can happen that you have to recover even a modern device.
So actually it depends on the platform you use how to get and keep and clean systen.
> Is there "configuration beyond configuration" or something?
Depends on the platform and what you use. On the SRX platform, there could be some internal certificates or any keys for encryption which you would need to save and restore as well. If you have any SLAX or Python scripts installed, they are erased as well.
> How could this work in a virtual chassis?
If you want to "install --format" a VC, then you have to shutdown all members, remove the VC cables, and perform the recovery procedure on every single device and let them boot without the VC cables connected to it. After the first VC member (= master) is configured, you can attach the remaining members step-by-step to let them form a VC.
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Original Message:
Sent: 01-12-2021 16:04
From: Unknown User
Subject: loader> install --format...: Cleanest way to upgrade Junos OS or stupid idea?
Hi everybody,
I just repaired a broken EX3300-24P using this method which was in a really bad state after a power outage. This worked like a charm.
So it came to my mind that maybe this could be the cleanest way to upgrade Junos OS:
1. backup configuration
2. Do a "full recovery" with the desired version and KB20643
3. import configuration
Could this work or do I miss something? Is there "configuration beyond configuration" or something?
How could this work in a virtual chassis?
Thanks for your opinion and many greets
Stephan