what is the purpose of vlan.dat file on the flash. I accidently deleted the vlan.dat file and rebooted the router. Will that be an issue?

I tried with Sandisk 256MB CF. I formatted it and copied the latest version of IOS,(I can see "Jun 26 10:18:15.546 EDT: %FILESYS-5-CF: CompactFlash inserted" as sh ver output)After inserting the new CF , the router reboots and comes to the enable mo...