Some NFS file transfers fail and hang automounting

From Linux NFS

Symptoms

• Given a file "foo" of 50Mb on a remote machine "remote".
  • This command will never finish

    <localmachine $> cp /remote_mount_point/foo bar 

  • bar will have a size less than foo.
  • automounting of the local machine is hung.

• The following message will show up in /var/log/messages

kernel: Callback slot table overflowed

• The problem doesn't occur if foo has a size less than 10Mb
• The final size of bar appears to be random

• This incident occurs with:

  sunrpc.tcp_slot_table_entries = 16

• This incident does NOT occur with:

  sunrpc.tcp_slot_table_entries = 32