From: "Stanley, Jon" <Jon.Stanley@savvis.net>
Subject: Re: [Linux-cluster] [RFC] NLM lock failover admin interface
Date: Mon, 12 Jun 2006 09:45:03 -0500
Message-ID: <9A6FE0FCC2B29846824C5CD81C6647B902207776@s228130hz1ew08.apptix-01.savvis.net>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
To: "linux clustering" <linux-cluster@redhat.com>,
	<nfs@lists.sourceforge.net>
Sender: nfs-bounces@lists.sourceforge.net
Errors-To: nfs-bounces@lists.sourceforge.net

 
> -----Original Message-----
> From: linux-cluster-bounces@redhat.com 
> [mailto:linux-cluster-bounces@redhat.com] On Behalf Of Wendy Cheng
> Sent: Monday, June 12, 2006 12:26 AM
> To: nfs@lists.sourceforge.net
> Cc: linux-cluster@redhat.com
> Subject: [Linux-cluster] [RFC] NLM lock failover admin interface
> 
NOTE - I don't use NFS functionality in Cluster Suite, so my coments may
be entirely meaningless.

> 
> 1. /proc interface, say writing the fsid into a /proc directory entry
> would end up dropping all NLM locks associated with the NFS 
> export that
> has fsid in its /etc/exports file.

This would defintely have it's advantages for people who know what
they're doing - they could drop all locks without unexporting the
filesystem.  However, it also gives people the opportunity to shoot
themselves in the foot - by eliminating locks that are needed.  After
weighing the pros and cons, I really don't think that any method
accessible via /proc is a good idea.

> 
> 2. Adding a new flag into "exportfs" command, say "h", such that
> 
>    "exportfs -uh *:/export_path"
> 
> would un-export the entry and drop the NLM locks associated with the
> entry.
> 

This is the best of the three, IMHO.  Gives you the safety of *knowing*
that the filesystem was unexported before dropping the locks, and
preventing folks from shooting themselves in the foot.

The other option that was mentioned, a separate lockd for each fs, is
also a good idea - but would require a lot of coding no doubt, and
introduce more instability into what I already preceive as an unstable
NFS subsystem in Linux (I *refuse* to use Linux as an NFS server and
instead go with Solaris - I've had *really* bad experiences with Linux
NFS under load - but that's getting OT).


_______________________________________________
NFS maillist  -  NFS@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nfs