From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00F6EC4363D for ; Wed, 7 Oct 2020 00:18:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 831D820739 for ; Wed, 7 Oct 2020 00:18:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="eoxl4sNn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726560AbgJGASQ (ORCPT ); Tue, 6 Oct 2020 20:18:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725972AbgJGASP (ORCPT ); Tue, 6 Oct 2020 20:18:15 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9010C061755 for ; Tue, 6 Oct 2020 17:18:15 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 8EDC7367; Tue, 6 Oct 2020 20:18:14 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 8EDC7367 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1602029894; bh=PBP3kZ0UmnFXH3VUn/gGdbjdMG+BcQaacF2gsZp143Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eoxl4sNnGEhoPd3o7BIVNMO0nfXF8/7SjhuGqh/pAIdwBaPSvgL9H/Y8t83vxU3EM 9IEhCNhY/CUcgBw+tbaTByFw359ezYSUREkfpaALpuZzI6RSLoQ+Bofwk+BFcpaBFt ZyhetgbCtBsdbsFZpLcWU4QL21Vw49r6OK/zYdr0= Date: Tue, 6 Oct 2020 20:18:14 -0400 From: "J. Bruce Fields" To: Olga Kornievskaia Cc: Benjamin Coddington , linux-nfs Subject: Re: unsharing tcp connections from different NFS mounts Message-ID: <20201007001814.GA5138@fieldses.org> References: <20201006151335.GB28306@fieldses.org> <95542179-0C20-4A1F-A835-77E73AD70DB8@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Tue, Oct 06, 2020 at 05:46:11PM -0400, Olga Kornievskaia wrote: > On Tue, Oct 6, 2020 at 3:38 PM Benjamin Coddington wrote: > > > > On 6 Oct 2020, at 11:13, J. Bruce Fields wrote: > > > > > NFSv4.1+ differs from earlier versions in that it always performs > > > trunking discovery that results in mounts to the same server sharing a > > > TCP connection. > > > > > > It turns out this results in performance regressions for some users; > > > apparently the workload on one mount interferes with performance of > > > another mount, and they were previously able to work around the > > > problem > > > by using different server IP addresses for the different mounts. > > > > > > Am I overlooking some hack that would reenable the previous behavior? > > > Or would people be averse to an "-o noshareconn" option? > > > > I suppose you could just toggle the nfs4_unique_id parameter. This > > seems to > > work: > > > > flock /sys/module/nfs/parameters/nfs4_unique_id bash -c "OLD_ID=\$(cat > > /sys/module/nfs/parameters/nfs4_unique_id); echo imalittleteapot > > > /sys/module/nfs/parameters/nfs4_unique_id; mount -ov4,sec=sys > > 10.0.1.200:/exports /mnt/fedora2; echo \$OLD_ID > > > /sys/module/nfs/parameters/nfs4_unique_id" > > > > I'm trying to think of a reason why this is a bad idea, and not coming > > up > > with any. Can we support users that have already found this solution? > > > > What about reboot recovery? How will each mount recover its own state > (and present the same identifier it used before). Client only keeps > track of one? Looks like nfs4_init_{non}uniform_client_string() stores it in cl_owner_id, and I was thinking that meant cl_owner_id would be used from then on.... But actually, I think it may run that again on recovery, yes, so I bet changing the nfs4_unique_id parameter midway like this could cause bugs on recovery. --b.