Why vlan.dat is saved in Flash Memory not in NVRAM in VTP Server Mode?

[Iluvnetwork]

In VTP Server Mode, switch saves VLAN configuration information in a file named vlan.dat in Flash Memory.

In VTP Transparent Mode, switch saves VLAN configuration information in a file named vlan.dat in NVRAM.

In VTP Client Mode, switch saves VLAN information in RAM only.

I understand that switch can only save VLAN information in RAM only in VTP Client Mode. My question is why in VTP Server Mode, switch saves VLAN configuration information in Flash Memory not in NVRAM. My understanding is that compressed files such as IOSs are saved in Flash memory and uncompressed files such as startup-config files are saved in NVRAM; Startup-Config files are saved in NVRAM because NVRAM is faster than Flash Memory.

Can anyone explain to me why?    

[Mark Malone · Accepted solution]

Hi
vlan.dat is stored in flash or nvram whether transparent/server etc not sure what platform your looking at but it varys per device , nearly all my devices 29/26/38s etc store it in flash not nvram whether trans or server

"Remember Flash is a type of non-volitile RAM or NVRAM. Depending on the switch model the vlan.dat file is stored in either NVRAM or Flash. It does depend on the switch."

xxxxxx#dir flash:vlan?
flash:vlan.dat

xxxxxx#sh vtp status | i Tra
VTP Traps Generation : Disabled
VTP Operating Mode : Transparent


Directory of nvram:/

37 -rw- 20675 <no date> startup-config
38 ---- 5860 <no date> private-config
1 ---- 37 <no date> persistent-data
2 -rw- 962 <no date> ifIndex-table
3 -rw- 590 <no date> IOS-Self-Sig#3232.cer

[Julio E. Moisa · Accepted solution]

Hi

Additional to Mark's post check this link:

https://learningnetwork.cisco.com/thread/36951

:-)

[ThomasDL41]

The truth:

VLAN information is stored in flash:vlan.dat.   VTP information is stored in NVRAM.

VTP information means "VTP domain", "VTP mode", "VTP password", etc.  This is the VTP information that is stored in NVRAM.

VTP servers store "VLAN" information in flash:vlan.dat.

VTP info (VTP domain, VTP password, etc.) is stored in NVRAM.

VLAN info (VLAN ID #, VLAN name, etc.) is stored in flash:vlan.dat.

VTP information is not the same as VLAN information.