From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from minas.ics.muni.cz ([147.251.4.40]:54847 "EHLO minas.ics.muni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752931Ab2DQOfG (ORCPT ); Tue, 17 Apr 2012 10:35:06 -0400 Date: Tue, 17 Apr 2012 16:34:48 +0200 From: Lukas Hejtmanek To: Jeff Layton Cc: linux-nfs@vger.kernel.org, jiri.horky@cesnet.cz Subject: Re: NFSv4 high availability setups Message-ID: <20120417143448.GU32132@ics.muni.cz> References: <20120405103124.GV4752@ics.muni.cz> <20120405073901.63d1c749@tlielax.poochiereds.net> <20120410125552.GC5074@ics.muni.cz> <20120410091321.1be1a87e@tlielax.poochiereds.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 In-Reply-To: <20120410091321.1be1a87e@tlielax.poochiereds.net> Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi, On Tue, Apr 10, 2012 at 09:13:21AM -0400, Jeff Layton wrote: > Nope. It'll all work just great...until it doesn't. I don't have any > specific failure scenarios, but most of the problems will be issues > with state recovery when a server node is restarted. > > That may manifest in different ways -- problems reclaiming locks for > instance, or even silent data corruption depending on the application. would it work if I relax active-active scenario to just active-passive in the following way: Server A actively exports /export/A Server B actively exports /export/B Server B is passive backup for Server A Server A is passive backup for Server B would it work to migrate the failed Server B to Server A so that Server A will server both /export/A and /export/B? There will be a problem with v4recovery dir. Would it be possible just to merge v4recovery from Server B to Server A (nfs export would be stopped while merging v4recovery). It seems that cp -r B/v4recovery/* A/v4recovery/ would do all the things. Am I right? Do I need to copy recovery state if I delay migration of the failed Server B to Server A for 91 secs? I.e., longer than lease expiry time.. Or do I still need a record for the client in v4recovery dir in such a case? -- Lukáš Hejtmánek