I have a bunch of compute clients working on jobs, saving output data to a NAS machine. All machines are centos 6.2. They mount it via automount NFS, with a timeout of 1200 (default config).
The NAS machine needs to be restarted.
If I can restart the machine within that 1200s (20 minute) window, will the clients just block on IO until it comes back up? A minor interruption (pause) in service is ok, as long as it doesn't cause the running processes to error out.
If necessary I could loop through and SIGSTOP all job processes, restart and resume them -- I just don't want to break the open file handles.
How can I run a restart like this without killing processes with open files?