What happen if battery of NVRAM is discharged or removed

This article written based on the case raised from the customer of Extremenetworks. Same symptom can be shown on other switch using NVRAM to save clock, configuration etc.

I want to share what happen if battery of NVRAM is discharged or removed, and what is the best workaround for NVRAM battery problem.

Platform:
Summit switches, but similar symptom can be shown from other devices using NVRAM for saving configuration, clock etc.

Symptoms:

When the switch powered on,

• it fail to boot with secondary image even it configured to reboot with secondary image, but boot with primary image.
• Switch configuration became factory default, and it cause L2 loop at the site.
• when  “show switch” command is executed, the boot count shown as 1, and the current year shown as 1919.

If NVRAM battery is removed from the switch, and if the switches is powered off/on, then

• boot with primary image, factory default configuration, boot count reset to 1, current year shown as 1919.

But this symptom not happened during the soft reboot.

Solution:

           If same symptoms happened, then check the NVRAM battery status.

Workaround

• Save the current configuration as default.xsf, so prevent the switch from resetting to factory default
• Save the currently used image as the primary image, so the switch can maintain same image even issue happened.

Use the NTP server to maintain correct time even in case issue happened