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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D79F6C433DF for ; Thu, 18 Jun 2020 13:49:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD6FA2082F for ; Thu, 18 Jun 2020 13:49:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="dOtH3Q4z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730360AbgFRNtR (ORCPT ); Thu, 18 Jun 2020 09:49:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730345AbgFRNtP (ORCPT ); Thu, 18 Jun 2020 09:49:15 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF156C06174E; Thu, 18 Jun 2020 06:49:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=n9BaMVUCaVyJLD8yPDoe2PtpH60KSIZHmuyQxc4LjSI=; b=dOtH3Q4zNMES4xCLLlwm8XQOUW toJqrLIhJk4+L36KIPooyLY2K+UIaOFzzH+nOTfHQn4SIFVcucJOYD41Peuylc3Cmoo+Kbx3eznT+ yiJ8B0pqNDI5LBVOETjtrjUw8ikMKL3NhEOyPbWqbZl2a2o9feAYkULaMnIO3N0zzEUwh5XJIrtY9 SXwQo/k2otshC7Kt906KTwQm27+bhgksFt+1c2mNvKd+nsB1pFykEHIfOCJnl8DfCsCn9JHfXlNoY nweICrbUL4Aq3invuQwb2yeiRR40IQLPk7otS2mHGH3fbstvgLwQLZlGrPbT7v0O4Y/UUefbSPZpw xVB/m5gA==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jluue-0006zB-1Q; Thu, 18 Jun 2020 13:49:04 +0000 Date: Thu, 18 Jun 2020 06:49:04 -0700 From: Christoph Hellwig To: Simon Arlott Cc: Christoph Hellwig , "James E.J. Bottomley" , "Martin K. Petersen" , Jonathan Corbet , Linux Kernel Mailing List , linux-scsi@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH] scsi: sd: stop SSD (non-rotational) disks before reboot Message-ID: <20200618134904.GA26650@infradead.org> References: <499138c8-b6d5-ef4a-2780-4f750ed337d3@0882a8b5-c6c3-11e9-b005-00805fc181fe> <20200618072138.GA11778@infradead.org> <9877e7de-d573-694b-2b75-95192756684b@0882a8b5-c6c3-11e9-b005-00805fc181fe> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9877e7de-d573-694b-2b75-95192756684b@0882a8b5-c6c3-11e9-b005-00805fc181fe> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Thu, Jun 18, 2020 at 01:25:18PM +0100, Simon Arlott wrote: > On 18/06/2020 08:21, Christoph Hellwig wrote: > > On Wed, Jun 17, 2020 at 07:49:57PM +0100, Simon Arlott wrote: > >> Avoiding a stop of the disk on a reboot is appropriate for HDDs because > >> they're likely to continue to be powered (and should not be told to spin > >> down only to spin up again) but the default behaviour for SSDs should > >> be changed to stop them before the reboot. > > > > I don't think that is true in general. At least for most current server > > class and older desktop and laptop class systems they use the same > > format factors and enclosures, although they are slightly divering now. > > > > So I think this needs to be quirked based on the platform and/or > > enclosure. > > Are you referring to the behaviour for handling HDDs or SSDs? All of the above. > > For HDDs, the default "1" option could mean "automatic" and apply to > rotational disks when power loss is expected. > > For SSDs, I don't think an extra stop should ever be an issue. Extra shutdowns will usually cause additional P/E cycles.