wr erase command doesn't erase all config

[PolarPanda]

Hi,

         i'm trying to use "wr erase" command to erase all the config, but after reload. I can still see the previous stack switch provision, vtp setup and vlans. Does anyone know the reason? Thanks

[balaji.bandi]

what is the model of the switch and what code running ?

[M02@rt37]

Hello @PolarPanda,

Please share #show version output and/or tell us the value of the config-register.

Thanks.

[Joseph W. Doherty]

Well, if you have a switch that was using VTP client or server mode, although it shows VLAN information in the config, it also maintains a separate VLAN database, independent of the config.  Also, some switches (?) might also have this VLAN DB when VTP mode transparent or off is being used, but that might be wiped at some point, sync'ed to the config.  (Possibly on erase start-up, or after booting without a start-up config.)

Even if you boot without a start-up config, running config will show some defaults (based on the IOS).  Plus, I recall (?), some config information, like the VLAN DB, isn't saved in or just in the start-up config file.  (I recall, on some later platforms, if you boot without a start-up config, then save running to start-up, then compare the two, you'll find differences.)

[Leo Laohoo · Accepted solution]

VLAN database will never be deleted with the command "write erase". 

[Martin L · Accepted solution]

Depending on switch model, I think the best way to erase info and vlan database is to go into "switch mode", aka bios of switch before he/she boots.  usually done by pressing and holding mode button for few seconds during booting up.  There u can delete config and vlan database. 

previous stack switch provision -- are they still connected? disconnect stack cables reboot into "bios/switch" mode and edit stack_member_id filed in every switch. 

vtp info and vlans must be delete by removing vlan.dat file in flash. 

Regards, ML
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[Joseph W. Doherty]

I recall (???) deleting VLAN.dat from flash, while IOS running.  But, recollections get a bit fuzzy when one has NOT tried something in 5 or more years.  (Also, if this can be done at all, perhaps VTP mode has to be running as transparent or off.)