[Gluster-users] NFS mounts with glusterd on localhost - reliable or not?

Whit Blauvelt whit.gluster at transpect.com
Thu Jul 19 12:35:45 UTC 2012

On Thu, Jul 19, 2012 at 05:16:24AM -0400, Krishna Srinivas wrote:
> It was pretty confusing to read this thread. Hope I can clarify the
> questions here.

Thanks. I was confused.

> The other discussion in this thread was related to NLM which has been
> implemented in 3.3.0. This is to support locking calls from the NFS
> clients to support fcntl() locking for the applications running on nfs
> client. NLM server is implemented in glusterfs as well as kernel. NLM
> server implemented in kernel is used by kernel-nfsd as well as
> kernel-nfs-client. Hence if you have an nfs mount point, the
> kernel-nfs-client automatically starts kernel NLM server. So if
> glusterfs-nfs process is already running on a system (and hence it
> also runs its own NLM server) and if you try to do "mount -t nfs
> someserver:/export /mnt/nfs" on the same system it fails as
> kernel-nfs-client won't be able to start kernel-NLM-server (because
> glusterfs NLM server would have already registered with portmapper for
> NLM service and hence  kernel-NLM-server registration with portmapper
> fails). Workaround is "mount -t nfs -o nolock someserver:/export
> /mnt/nfs" if you really want to have an nfs mount on the same machine
> where glusterfs-nfs process is running.

So, if you want to run both at once, only one can lock. Is the architecture
of NLM such that there could never be a single NLM server for both Gluster
and kernel (whether that single server be Gluster's or kernel's)? 


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