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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C27C0C433EF for ; Thu, 24 Mar 2022 01:18:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=aeKnD278gsrWyP8wQB2hD8XvRI7hUSlZIoaZT77WpCI=; b=NoHdkJlXI6nNmjAXvI7gSOGME4 /7tcc1f1+xpEGFF6ErnosBwKE1oYpwsyJDHdEq2hQhK7LtIAoUWiZGOlDUx5CMAGeXf27J3K2vwCN 6Z1T+w2YiDDkhedi2hFMfW+57tjjU9wIK2SkKcSpYau5JDxnxgO1JXTNUTrpgMYHRVUOGwc95mybP g8+ppDdYpExk5IhF1lbqBfQHBN2ZPXZZSdOey4S35dJj2CAeUUtKTZX58zGxXf7tyCOKETrLbg1Jf kXS80dIRBpTCPPsUdhFTt5fnHnEWWsm7rfCGXZ7n011CEeI8X7KrmovDWpn7ipmmh1Z+nzsXK7A3q 8d/nCAJg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nXC72-00FIWQ-Vi; Thu, 24 Mar 2022 01:18:05 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nXC6z-00FIVi-Rm for linux-nvme@lists.infradead.org; Thu, 24 Mar 2022 01:18:03 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1648084680; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aeKnD278gsrWyP8wQB2hD8XvRI7hUSlZIoaZT77WpCI=; b=Hdjaz4aPadeE38sgu9W2uArmB95KJF9HN+1SNyBV8kIXerPTYL4aYjPwL+R2SqmJcV1Crf GF5xLFqC3zzxsAcdxrNLlDE9punY7/tg4vf/vUXPW3I9c90RMaIJ3FLKpqNulXZM22cKq8 p9t3qZRbL45wBzfyzURuRpy3aedNa1o= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-628-vvQJKOV7ORuyhBfwSovUgQ-1; Wed, 23 Mar 2022 21:17:58 -0400 X-MC-Unique: vvQJKOV7ORuyhBfwSovUgQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7CFB4185A79C; Thu, 24 Mar 2022 01:17:58 +0000 (UTC) Received: from [10.22.19.101] (unknown [10.22.19.101]) by smtp.corp.redhat.com (Postfix) with ESMTP id 54C3340D282D; Thu, 24 Mar 2022 01:17:58 +0000 (UTC) Message-ID: <4e1aaadb-0044-6367-e4a6-e3f159fa007c@redhat.com> Date: Wed, 23 Mar 2022 21:17:58 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.0 Subject: Re: [LSF/MM/BPF TOPIC] dispersed namespaces revisited To: Hannes Reinecke , Christoph Hellwig Cc: "lsf-pc@lists.linux-foundation.org" , "linux-nvme@lists.infradead.org" References: <521666e9-9114-9c2d-c680-a52defb45f8a@suse.de> From: John Meneghini Organization: RHEL Core Storge Team In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jmeneghi@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220323_181801_997703_98C59791 X-CRM114-Status: GOOD ( 21.67 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org I agree with Christoph that the current conception of dispersed namespaces fundamentally breaks the NVMe storage object model. However, there have been several ideas proffered at FMDS to fix this and I think people are willing to make changes to TP-4034 to redress this problem. I think this is a topic that needs to be discussed at LSF/MM or ALPSS. /John On 3/23/22 13:16, Hannes Reinecke wrote: > On 3/23/22 17:27, Christoph Hellwig wrote: >> Hi Hannes, >> >> the answer is pretty simple:  dispersed namespaces are a bad idea and >> will not be implemented in Linux, and this has been the stance since >> this was first proposed. >> >> If these vendors want Linux support they can already trivially >> implement virtual subsystems and are highly encouraged to do so. >> (the concept of domains actually makes it even simpler than in >> the beginning). > > Guess what, that's what I have been proposing. > And they have (somewhat) agreed. > > I just wanted to use LSF to get everyone on board, and then be able to come with a proposal to NVMexpress which I know will be > acceptable from the Linux community. > > I have a patchset ready implementing virtual subsystems based on the NS UUID (and thereby putting each namespace into a separate > subsystem). > At this time it's just a PoC to demonstrate the concept; specification is not even proposed, and so it's hard to code against. > > I can send a pointer to my kernel.org branch if you like. > > Cheers, > > Hannes