[Nbd] nbd hangs when disconnection the network

[Steven Yelton <steveny@...78...>]

I have a problem with the nbd-client hanging when the network cable is

removed from the server.  Here is my setup:

storage1:
 exporting raid1a
 exporting raid1c

storage2:
 exporting raid1b

client machine:
md0 is raid5 with nbd{0,1,2}

The raid builds and runs fine.  If I kill the nbd-server on 'storage2' 
the raid immediately goes into a 'degraded' state (exactly as I would 
expect).  However, if I just pull the network connection from 
'storage2', md0 just hangs (even `cat /proc/mdstat` hangs).  After 
several minutes (10, maybe) the client seems to notice the server is 
dead (Error: Connect: No route to host) and the raid is degraded.

What can I do to decrease the time it takes for nbd-client to realize it 
can't get to the storage machine anymore?

Thanks in advance,
Steven