From: James Yarbrough Date: Mon, 07 Aug 2006 13:14:30 -0700 Subject: [Cluster-devel] Re: [NFS] [PATCH 0/3] NLM lock failover References: <44A41246.2070106@redhat.com> <1154397341.3378.10.camel@localhost.localdomain> <1154683665.21040.2431.camel@hole.melbourne.sgi.com> <1154698079.3378.2.camel@localhost.localdomain> <1154703362.3378.45.camel@localhost.localdomain> <1154706709.4727.21.camel@localhost> <1154756682.3384.34.camel@localhost.localdomain> <1154923557.29877.106.camel@hole.melbourne.sgi.com> Message-ID: <44D79F26.B93E5C00@sgi.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit > > take-over server: > > B-1. mount the subject filesystem > > B-2. "echo 1234 > /proc/fs/nfsd/nlm_set_ip_grace" > > B-3. "rpc.statd -n 10.10.1.1 -N -P /shared_storage/sm_10.10.1.1" > > B-4. bring up 10.10.1.1 > > B-5. re-export the filesystem > > Umm, don't you want to do B-3 after B-4 and B-5 ? Otherwise > clients might racily fail on the first try. I don't think they will necessrily fail. It depends on whether the server sends ICMP unreachable messages and how the client responds to those. In any case, I think the ordering should be B-5, B-4, and B-3 last. One can argue about the ordering of B-3 and B-4, but if exporting (B-5) does not happen before bringing up the IP address (B-4), clients can get ESTALE replies. For better transparency, it's probably best to avoid ESTALE. It's probably OK to do step B-3 after bringing up the IP address since that will mimic what happens during boot. > > Also, just curious here, when do you purge the clients' ARP caches? I don't think you can actually do a purge from the server explicitly. You should get the desired result when the IP address (10.10.1.1 in the above example) is brought up. There's a gratuitous ARP that goes with that step. -- jmy at sgi.com 650 933 3124 Blow up the mailbox!