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=-2.3 required=3.0 tests=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 28E98C3B186 for ; Mon, 10 Feb 2020 21:52:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2A502082F for ; Mon, 10 Feb 2020 21:52:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727411AbgBJVwZ (ORCPT ); Mon, 10 Feb 2020 16:52:25 -0500 Received: from mail104.syd.optusnet.com.au ([211.29.132.246]:35364 "EHLO mail104.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727254AbgBJVwZ (ORCPT ); Mon, 10 Feb 2020 16:52:25 -0500 Received: from dread.disaster.area (pa49-179-138-28.pa.nsw.optusnet.com.au [49.179.138.28]) by mail104.syd.optusnet.com.au (Postfix) with ESMTPS id A60EE7EB6F2; Tue, 11 Feb 2020 08:52:23 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1j1Gyc-0003E9-Qv; Tue, 11 Feb 2020 08:52:22 +1100 Date: Tue, 11 Feb 2020 08:52:22 +1100 From: Dave Chinner To: Muhammad Ahmad Cc: linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, Tim Walker Subject: Re: [LSF/MM/BPF TOPIC] Multi-actuator HDDs Message-ID: <20200210215222.GB10776@dread.disaster.area> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=W5xGqiek c=1 sm=1 tr=0 a=zAxSp4fFY/GQY8/esVNjqw==:117 a=zAxSp4fFY/GQY8/esVNjqw==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=IkcTkHD0fZMA:10 a=l697ptgUJYAA:10 a=07d9gI8wAAAA:8 a=7-415B0cAAAA:8 a=q5T8XEN1vGXhI3tkvFYA:9 a=QEXdDO2ut3YA:10 a=e2CUPOnPG4QKp8I52DXD:22 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Feb 10, 2020 at 12:01:13PM -0600, Muhammad Ahmad wrote: > Background: > As the capacity of HDDs increases so is the need to increase > performance to efficiently utilize this increase in capacity. The > current school of thought is to use Multi-Actuators to increase > spinning disk performance. Seagate has already announced it’s SAS > Dual-Lun, Dual-Actuator device. [1] > > Discussion Proposal: > What impacts multi-actuator HDDs has on the linux storage stack? > > A discussion on the pros & cons of accessing the actuators through a > single combined LUN or multiple individual LUNs? In the single LUN > scenario, how should the device communicate it’s LBA to actuator > mapping? In the case of multi-lun, how should we manage commands that > affect both actuators? What ground does this cover that wasn't discussed a couple of years ago at LSFMM? https://lwn.net/Articles/753652/ Cheers, Dave. -- Dave Chinner david@fromorbit.com