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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B1B8C433FE for ; Thu, 4 Nov 2021 18:09:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E08F860EC0 for ; Thu, 4 Nov 2021 18:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234088AbhKDSM2 (ORCPT ); Thu, 4 Nov 2021 14:12:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232152AbhKDSM0 (ORCPT ); Thu, 4 Nov 2021 14:12:26 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1328C061714; Thu, 4 Nov 2021 11:09:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=X/zx02lrok+YXE3fHYCnesmy30oZEd5gQFjWswEssO8=; b=Sbg76vqBUrKRwSH8VKRkJgiUCC r1oyKJ79d1QE9fOCCZaLTLXMc2ew6uKuULTjgBflx8d78VPVr2homn7rL3kQVHvP7Ak9/wM0MbpSy YSrJUXTFHpxtX4i3XpHfoy8u4fm08G+Cx16cTwYn/LBCFS7Lv3f39xVI6zKCrHqps5FJzI6XW50qi 8xgjF5t15JvLZTKg6czUDnDkLd8NyrCoKV5fYiMDj6WPdVlgUuSxgdjCS10DIR/kWUthyM54DNI3M 3ulIl7eI4ED25BAW7Mc3MlXqYoWF5f6UgyROaM1IDdmMYVmXaRrN/V/m7JIC73SF58NYKDj27R5M0 Cc4GufhA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mih7J-0062bO-LC; Thu, 04 Nov 2021 18:06:22 +0000 Date: Thu, 4 Nov 2021 18:05:37 +0000 From: Matthew Wilcox To: Christoph Hellwig Cc: Dan Williams , "Darrick J. Wong" , Jane Chu , "david@fromorbit.com" , "vishal.l.verma@intel.com" , "dave.jiang@intel.com" , "agk@redhat.com" , "snitzer@redhat.com" , "dm-devel@redhat.com" , "ira.weiny@intel.com" , "vgoyal@redhat.com" , "linux-fsdevel@vger.kernel.org" , "nvdimm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-xfs@vger.kernel.org" Subject: Re: [dm-devel] [PATCH 0/6] dax poison recovery with RWF_RECOVERY_DATA flag Message-ID: References: <2102a2e6-c543-2557-28a2-8b0bdc470855@oracle.com> <20211028002451.GB2237511@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 04, 2021 at 10:43:23AM -0700, Christoph Hellwig wrote: > Well, the answer for other interfaces (at least at the gold plated > cost option) is so strong internal CRCs that user visible bits clobbered > by cosmic rays don't realisticly happen. But it is a problem with the > cheaper ones, and at least SCSI and NVMe offer the error list through > the Get LBA status command (and I bet ATA too, but I haven't looked into > that). Oddly enough there has never been much interested from the > fs community for those. "don't realistically happen" is different when you're talking about "doesn't happen within the warranty period of my laptop's SSD" and "doesn't happen on my fleet of 10k servers before they're taken out of service". There's also a big difference in speeds between an NVMe drive (7GB/s) and a memory device (20-50GB/s). The UBER being talked about when I was still at Intel was similar to / slightly better than DRAM, but that's still several failures per year across an entire data centre that's using pmem flat-out.