Is it normal that when unplugging a cable on one of the 6500 VSS switches it loses configuration?

[lilili]

6500 VSS primary switch lost its config entirely, after we eunplugged the cable to force it to reboot.

Is it an expected behavior (and why), or is it due to an issue ?

thanks

[Reza Sharifi]

No, that is not the expected behavior. Most likely there is a bug in the version of IOS you are running that causes it to lose its config.

HTH

[lilili]

ok thanks. couple more details: the power cord was pulled out of the primary switch only, while the secondary switch took over. however - secondary switch had high CPU (99%)

would that have anything to do with the fact that the config was lost on the primary? for some reason the cisco TAC who was looking at that case at that time said that was an expected occurrence, which did not make sense to me, frankly... 

[Leo Laohoo]

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@lilili wrote:

the power cord was pulled out of the primary switch only, while the secondary switch took over. however - secondary switch had high CPU (99%) 

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Depends on the IOS, chassis uptime and the configuration, there are a lot of variables why the CPU is very high.  But it is still very unusual for a VSS to be reporting a 99% CPU.  

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@lilili wrote:

would that have anything to do with the fact that the config was lost on the primary?

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Ok, so when the primary controller was rebooted, it came back with NO CONFIG.  Right?  But the secondary was able to take over and the secondary was able continue with config.  Correct? 

My focus is the primary.  Since they are both in VSS, there is no chance that someone wiped the config before the chassis rebooted.  I have never seen an IOS bug that wipes the startup config either.  This only leaves one possible cause:  The config-registry value has been set to 0x2142 (or something similar).

[Leo Laohoo]

As what Reza said, no it's not normal. 

Please check the config-register value.  The recommended value is either 0x2101 or 0x2102.