Re: Stopping NFS, ip address take over, zero-copy NFS for 2.4.21, and misc

[Matt Schillinger <mschilli@vss.fsi.com>]

On Thu, 2003-09-18 at 16:21, James Pearson wrote:
> Chris Worley wrote:
> >
> > 2) IP address takeover between NFS servers.
> > 
> > With NFS stateless, and not running lock servers, I thought a simple IP
> > address takeover scheme (when an I/O server goes down, another just adds
> > the failed server's IP address as a virtual interface) would allow
> > clients to immediately renegotiate with the same IP address pointing to
> > another NFS server (serving the same partitions).  The take-over is
> > successful: the clients can communicate with the new I/O server, but I
> > get "permission denied" (as root or otherwise) on the NFS mounted
> > partitions most of the time (sometimes it works).
> > 
> > What am I missing?
> 
> I don't know a lot about NFS fail over, but I guess unless the take-over 
> server has a copy (or the same copy) of /var/lib/nfs/rmtab, then you 
> will get "permission denied" - the server needs an entry for each 
> client. I guess it works some of the time as the take-over server has a 
> 'valid' entry in its rmtab file for that client.
>

Yes, i made a little daemon that for each exported directory, generates
a 'directory specific' rmtab file in
/path/to/directory/.nfs_cluster/rmtab. It updates each export directory
every 2 seconds and copies the rmtab to rmtab.old , then generates a
clean rmtab. it has worked fine for me to prevent permission
denied/Stale NFS handles.

Upon the failover, after the filesystem is mounted by the 'takeover
server', the .nfs_cluster/rmtab is processed and added to
/var/lib/nfs/rmtab before exportfs instances are ran on the export
directories.

What are you using for failover?

I use heartbeat.

I also had to make a 2 second delay after IP takeover, for the IP to
actually be working, before I run the exportfs for the newly mounted
filesystem.

Matt Schillinger
mschilli@vss.fsi.com

 
> James Pearson
> 
> 
> 
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