From: Marc Eshel Subject: Re: [PATCH 0/4 Revised] NLM - lock failover Date: Wed, 25 Apr 2007 08:21:57 -0700 Message-ID: References: <462F6157.7060604@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: "J. Bruce Fields" , cluster-devel@redhat.com, Lon Hohberger , nfs@lists.sourceforge.net, nfs-bounces@lists.sourceforge.net To: Wendy Cheng Return-path: In-Reply-To: <462F6157.7060604@redhat.com> List-Id: "Discussion of NFS under Linux development, interoperability, and testing." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nfs-bounces@lists.sourceforge.net Errors-To: nfs-bounces@lists.sourceforge.net nfs-bounces@lists.sourceforge.net wrote on 04/25/2007 07:10:31 AM: > J. Bruce Fields wrote: > > On Thu, Apr 05, 2007 at 05:50:55PM -0400, Wendy Cheng wrote: > > > >> 1) Failover server exports filesystem with "fsid" option as: > >> /etc/exports entry> /mnt/shared/exports *(fsid=1234,sync,rw) > >> 2) Failover server dispatch rpc.statd with "-H" option. > >> 3) Failover server drops locks based on fsid by: > >> shell> echo 1234 > /proc/fs/nfsd/nlm_unlock > >> 4) Takeover server enters per fsid grace period by: > >> shell> echo 1234 > /proc/fs/nfsd/nlm_set_igrace > >> 5) Takeover server notifies clients for lock reclaim by: > >> shell> /usr/sbin/sm-notify -f -v floating_ip_address -P an_sm_directory > >> > > > > I don't understand statd and lockd as well as I should. Where exactly > > does the takeover server stop serving requests, and the failover server > > start? If this isn't done carefully, you can leave a window between > > steps 3 and 4 where a client could acquire a lock before its rightful > > owner reclaims it, right? > > > > > The detailed overall steps were described in the first email we sent > *long* time (> 6 months, I think) ago. The first step of the whole > process is tearing down the floating IP from the failover server. The IP > is not accessible until filesystem is safely fail-over and SM_NOTIFY > ready to be sent. I thought this is a solution for an active active server where a cluster file system can export the same file system from multiple NFS servers. Marc. > > Last round of discussion gave me an impression that as long as I rebased > the code into akpm's mm tree, these patches would get accepted. So I > have been quite careless in this submission and just realized people > have a very short memory :) .. Will do the write-up and put it somewhere > so we don't need to go thru this again. > > -- Wendy > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > NFS maillist - NFS@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/nfs ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs