NFS locking/ concurrency control

aarklon

what exactly is the locking /concurrency control mechanism used in NFS to prevent simultaneous updates in NFS ?


antonio batovanja

man nfs" would show you:

"The Network Lock Manager protocol is a separate sideband protocol used to manage file locks in NFS version 2 and version 3. To support lock recovery after a client or server reboot, a second sideband protocol -- known as the Network Status Manager protocol -- is also required.In NFS version 4, file locking is supported directly in the main NFS protocol, and the NLM and NSM sideband protocols are not used."


david schwarz


There is no need. If the updates are simultaneous, then neither is "more recent" than the other. So it doesn't matter. It only matters if a less recent update overwrites a more recent update.


maxwell lol

Some systems have/had a lock daemon running, and the NFS implementations coordinated with them to ensure concurrency.