On Mon, 09 Jun 2008 12:09:48 -0400 "Talpey, Thomas" <Thomas.Talpey@xxxxxxxxxx> wrote: > At 12:01 PM 6/9/2008, Jeff Layton wrote: > >On Mon, 09 Jun 2008 11:51:51 -0400 > >"Talpey, Thomas" <Thomas.Talpey@xxxxxxxxxx> wrote: > > > >> At 11:18 AM 6/9/2008, Jeff Layton wrote: > >> >No, it's not specific to NFS. It can happen to any "service" that > >> >floats IP addresses between machines, but does not close the sockets > >> >that are connected to those addresses. Most services that fail over > >> >(at least in RH's cluster server) shut down the daemons on failover > >> >too, so tends to mitigate this problem elsewhere. > >> > >> Why exactly don't you choose to restart the nfsd's (and lockd's) on the > >> victim server? > > > >The victim server might have other nfsd/lockd's running on them. Stopping > >all the nfsd's could bring down lockd, and then you have to deal with lock > >recovery on the stuff that isn't moving to the other server. > > But but but... the IP address is the only identification the client can use > to isolate a server. You're telling me that some locks will migrate and > some won't? Good luck with that! The clients are going to be mightily > confused. > Maybe I'm not being clear. My understanding is this: Right now, when we fail over we send a SIGKILL to lockd, and then send a SM_NOTIFY to all of the clients that the "victim" server has, regardless of what IP address the clients are talking to. So all locks get dropped and all clients should recover their locks. Since the service will fail over to the new host, locks that were in that export will get recovered on the "new" host. But, we just recently added this new "unlock_ip" interface. With that, we should be able to just send SM_NOTIFY's to clients of that IP address. Locks associated with that server address will be recovered and the others should be unaffected. > > > >> Failing that, for TCP at least would ifdown/ifup accomplish > >> the socket reset? > >> > > > >I don't think ifdown/ifup closes the sockets, but maybe someone can > >correct me on this... > > No, it doesn't close the sockets, but it sends interface-down status to them. > The nfsd's, in theory, should close the sockets in response. But, it's possible > (probable?) that nfsd may ignore this, and do nothing. It's just an idea. > That might be worth investigating, but sounds like it might cause problems with the services associated with IP addresses that are staying on the victim server. -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
