[Linux-cluster] GFS without fence system?

[孙俊伟]

Hi,
	if I have a cluster in which only one node do write operations to the storage 
at the same time, can I use GFS without fence system? Or use the fence system 
without hardware (such as FC switch, power switch) involved, do the fence operations automaticly immediately after the heartbeat detects a bad node.
	In reverse, at what condition that data corruption would happen without fence in 
GFS system? Two nodes write at the same LV|GFS|file|block (which?) at the same time?

Thanks for any reply!
Luckey.