Save VLAN.DAT in GNS/Dynamips

You know when you boot your router, the flash: is not saved and the vlan.dat that is saved on it is lost.. To remedy this, use a vlan.dat saved in nvram:

SW0(config)# vtp file nvram:/vlan.dat
SW0#dir nvram:
Directory of nvram:/

  123  -rw-        1683                      startup-config
  124  ----           5                      private-config
    1  -rw-           0                      ifIndex-table
    2  -rw-         780                      vlan.dat

There, now all your vlan/vtp config will be saved..