From: J. Bruce Fields Date: Wed, 25 Apr 2007 10:18:18 -0400 Subject: [Cluster-devel] Re: [NFS] [PATCH 0/4 Revised] NLM - lock failover In-Reply-To: <46156F3F.3070606@redhat.com> References: <46156F3F.3070606@redhat.com> Message-ID: <20070425141818.GA14729@fieldses.org> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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? --b.