I faced one issue. the scenario is like this.. before 2 months i configured one zoning at that time the devices are properly detected and established communication,at that time i think i forgot to run the command " copy running-conf startup-config " .Now i configured new zoning after enabling the new zone i lost the earlier Zone. why its happend like that ?? what is the technical reason behind this issue ??

switch model:cisco MDS 9124

note: not  rebooted the switch.