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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 B5918C433E2 for ; Sun, 13 Sep 2020 14:51:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 871772158C for ; Sun, 13 Sep 2020 14:51:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725940AbgIMOvK (ORCPT ); Sun, 13 Sep 2020 10:51:10 -0400 Received: from mail-pf1-f182.google.com ([209.85.210.182]:46185 "EHLO mail-pf1-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725928AbgIMOvI (ORCPT ); Sun, 13 Sep 2020 10:51:08 -0400 Received: by mail-pf1-f182.google.com with SMTP id b124so10391781pfg.13; Sun, 13 Sep 2020 07:51:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=yD/3+HTWCSur4HDtLCV8fvDnq1bK1MEzAie36X2p7qg=; b=mL2BSZMzosRveRie0tAdTFuZIZ8wh3saI75U2Ou8dFDSIMujQHDTZPbs27Ir0fU1u3 kE8AgzyKnGPZLqaA0AzzNYlAhtuttpXZ5ruXDibwil6zapjIyLwvhp9Yj2iZ4jiSacD8 dsvIpCcAVEg36hChZ7YwnWo3Ffuz/wxW9teMqtxF+gsty7gt4lL0cvcDtY0dbAQcznvg Aq9RFp381v2v6YwJ7asiCnWrPo7FGva3A7xY70iLpxZDfiXnKBzxgrJ4wV16krEvxaCb Xjldz2oWXK3yGuNMQ7KpCNoQ/Zz118Y/0Xh8rFshGWcaQiRPBMgpvqFaRDD8zD5rcfMD Xn/g== X-Gm-Message-State: AOAM530qWFUvS6WAOXH7uaABlLDrzlUdkwzjeMw27uPfUYY/4tvAFRht BKEyrDWOt2g7gWRwvKIgF1g+X9kQ8Rc= X-Google-Smtp-Source: ABdhPJy1eNyzHKHlattYdLX9dskcckIRLaBPkL1ooB1TJMKcMnieWKOESPVJ/KDYhPcfO0VGWlO4Nw== X-Received: by 2002:a63:2484:: with SMTP id k126mr4053548pgk.428.1600008666964; Sun, 13 Sep 2020 07:51:06 -0700 (PDT) Received: from [192.168.50.110] (c-73-241-217-19.hsd1.ca.comcast.net. [73.241.217.19]) by smtp.gmail.com with ESMTPSA id f28sm7673041pfq.191.2020.09.13.07.51.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 13 Sep 2020 07:51:06 -0700 (PDT) Subject: Re: [RFC] Reliable Multicast on top of RTRS To: Danil Kipnis Cc: linux-rdma@vger.kernel.org, linux-block@vger.kernel.org References: <3b2f6267-e7a0-4266-867d-b0109d5a7cb4@acm.org> From: Bart Van Assche Message-ID: <65ef9d97-fe45-923c-07ee-d53b975c2e0d@acm.org> Date: Sun, 13 Sep 2020 07:51:04 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 9/9/20 4:42 AM, Danil Kipnis wrote: > I have two general understanding questions: > - What is the conceptual difference between DRBD and an md-raid1 with > one local leg and one remote (imported over srp/nvmeof/rnbd)? Conceptually the difference is probably not that big. But the DRBD activity log makes a huge difference when recovering from a network disconnect or ungraceful shutdown. > - Is this possible to setup an md-raid1 on a client sitting on top of > two remote DRBD devices, which are configured in "active-active" mode? Are you perhaps referring to a single DRBD cluster? I'm not sure but I think that would make DRBD complain about concurrent writes. Thanks, Bart.