NFS: concurrent mounts may get delayed if one of the servers is not responding

Issue

Consider this scenario :

NFS_serverA -> unreachable, not responding, etc...
NFS_serverB -> reachable

If we launch two concurrent mounts to these servers, depending on the timing, mount to NFS_serverB can be delayed until NFS_serverA times out.

In some complex configs using i.e. autofs, this may cause delays if some broken mounts are involved, i.e. mounting /home for some users