[Gluster-users] NFS availability

[Stephan von Krawczynski]

On Wed, 30 Jan 2013 20:44:52 -0800
harry mangalam <harry.mangalam at uci.edu> wrote:

> On Thursday, January 31, 2013 11:28:04 AM glusterzhxue wrote:
> > Hi all,
> > As is known to us all, gluster provides NFS mount. However, if the mount
> > point fails, clients will lose connection to Gluster. While if we use
> > gluster native client, this fail will have no effect on clients. For
> > example:
>  mount -t glusterfs host1:/vol1  /mnt
> > 
> > If host1 goes down for some reason, client works still, it has no sense
> > about the failure(suppose we have multiple gluster servers).  
> 
> The client will still fail (in most cases) since host1 (if I follow you) is 
> part of the gluster groupset. Certainly if it's a distributed-only, maybe not 
> if it's a dist/repl gluster.  But if host1 goes down, the client will not be 
> able to find a gluster vol to mount.

For sure it will not fail if replication is used. 
 
> > However, if
> > we use the following:
>  mount -t nfs -o vers=3   host1:/vol1 /mnt
> 
> > If host1 failed, client will lose connection to gluster servers.
> 
> If the client was mounting the glusterfs via a re-export from an intermediate 
> host, you might be able to failover to another intermediate NFS server, but if 
> it was a gluster host, it would fail due to the reasons above.

kernel-nfs _may_ failover from server A to server B if B takes the original
server IP and some requirements are met.
You don't need an intermediate (re-exporting) server for this.

-- 
Regards,
Stephan