Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:62801 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030193AbcFNALJ (ORCPT ); Mon, 13 Jun 2016 20:11:09 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5E08lmS028918 for ; Mon, 13 Jun 2016 20:11:08 -0400 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0a-001b2d01.pphosted.com with ESMTP id 23gf59141y-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 13 Jun 2016 20:11:08 -0400 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 13 Jun 2016 18:11:07 -0600 Date: Mon, 13 Jun 2016 19:10:56 -0500 From: Malahal Naineni To: "J. Bruce Fields" Cc: sebastien cabaniols , linux-nfs@vger.kernel.org Subject: Re: does the linux NFS client support for failover to a replica share (read-only share) References: <20160613155237.GC17866@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160613155237.GC17866@fieldses.org> Message-Id: <20160614001055.GB2634@us.ibm.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: J. Bruce Fields [bfields@fieldses.org] wrote: > On Tue, Jun 07, 2016 at 10:02:19PM +0200, sebastien cabaniols wrote: > > Hello linux-nfs mailing list. > > > > I would like to know if the linux nfs client included in current > > versions of the kernel supports fail-over to a replica on another nfs > > server, I am using (manually) synchronized read-only shares... > > > > I found very few information on Google about this topic and I suspect > > this is not implemented. > > That's correct (unless I've missed something!). > > > I actually tried to setup this using SLES12SP1 (3.12.49 kernel) but I > > failed so far. I am not attached to this distribution/version in > > particular, just trying to see it working for real. > > > > ( I did some "rpcdebug -m nfs" session and it seems the fs_locations > > is not getting properly populated on my setup ) > > > > Any confirmation this should work or not would actually help me. > > > > THX. > > > > > > note from the exports man page: > > > > replicas=path@host[+host][:path@host[+host]] > > If the client asks for alternative locations for the > > export point, it will be given this list of alternatives. > > (Note that actual replication of the filesystem must be > > handled elsewhere.) > > Yes, the server side (assuming you've got the backend replication > working) is pretty easy, and should work (though I don't know if it's > gotten any testing). Bruce, we did test the server side couple years ago. I don't remember any issues on the server side. We did some rudimentary support on the client side (we were using rsync for replication and our exports were read-only!). I remember "find" having an issue with inode number change while it was running, but don't remember any other issues. The client patches never made it to mainline though. Regards, Malahal.