From: Wendy Cheng <wcheng@redhat.com>
Subject: Re: [Linux-cluster] [RFC] NLM lock failover admin interface
Date: Mon, 12 Jun 2006 23:39:31 -0400
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	linux clustering <linux-cluster@redhat.com>
To: "Stanley, Jon" <Jon.Stanley@savvis.net>
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On Mon, 2006-06-12 at 09:45 -0500, Stanley, Jon wrote:
>  
> > -----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

Jon, Thank you for review this - it helps !

-- Wendy

> > 
> > 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).
> 
> 
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