I have a number of NFS automounts in my Local directory node on 10.7. I am using a laptop and when I work at home I don't have access to the servers. As a result I often get beachballing Navigation Services dialogs for example, and logs are flooded with NFS error messages on this and that server not being reachable.
Is there some simple app (preferably a GUI one but scripting will do as well) which will disable the mounts when I am on WiFi or just not at work?
Try ControlPlane. It can perform all sorts of different actions, including mounting/unmounting network drives based on various triggers, including which WiFi network you're connected to.
It turns out this is not easily done. To disable automounts you need to actually remove them from the directory services. What I think I will try is just mounting the requisite volumes manually with the mount command when I am at work and unmounting them once I am home. This way no apps will get hung up on files that cannot be opened.
However it's a pity that automountd is so badly designed that it does not allow disabling or enabling mounts and does not have a hard limit on retires on a mount when the network configuration is stable.
