On Thu, 21 Jul 2011 15:40:05 +0200 Michael Schwartzkopff <misch@xxxxxxxxxxxxxxxxx> wrote: > Hi, > > setting up a linux NFS server cluster I experience a strange problem during a > failover. A client can access a file only after 60 to 90 seconds. On the line I > see a NFS4ERR_GRACE from the server to the client. > > I already set the /proc/fs/nfsd/nfsv4leastime to 10. > > Any other idea? > > For the tests I have a simple setup: > > One host with a simple script that simulates failover: > > #!/bin/bash > > ip a d 1.2.3.4/24 dev eth0 > exportfs -u *:/srv/nfs/home > exportfs -u *:/srv/nfs > /etc/init.d/nfsserver stop > # > /etc/init.d/nfsserver start > exportfs -o fsid=0,rw,crossmnt,no_root_squash *:/srv/nfs > exportfs -o fsid=1000,rw,mountpoint,no_root_squash *:/srv/nfs/home > ip a a 1.2.3.4/24 dev eth0 > This is normal. The grace period is there to allow clients to reclaim their state without other clients racing in and grabbing their locks on the new server, etc. You can play with /proc/fs/nfsd/nfsv4gracetime too but I'd be very leery of setting that too low. It should never be lower than the previous leasetime (see the comments on write_gracetime in the kernel). Note that setting the leasetime that small has an effect on performance too as the clients have to renew their state more frequently. It also affects the resiliency of your entire setup in the face of network partitions (including the network partition that occurs during failover). If the client can't reclaim its state during the grace period, then it's lost and nasty things can occur (like other clients stealing posix locks out from under you). -- 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
