From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id BE275139337 for ; Sat, 31 Jul 2021 12:13:02 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 81420E0896; Sat, 31 Jul 2021 12:12:54 +0000 (UTC) Received: from mail-oi1-f172.google.com (mail-oi1-f172.google.com [209.85.167.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 25A7CE0882 for ; Sat, 31 Jul 2021 12:12:53 +0000 (UTC) Received: by mail-oi1-f172.google.com with SMTP id z26so17299268oih.10 for ; Sat, 31 Jul 2021 05:12:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=FQylCCOrbd2Q7UBRYla9jU84Mv8BoLlSZFv+qDd7Qz0=; b=uD+fdb06uJu8b8W5mfzoCGTVpuzFVsTtKaozRE2BLglqqoCj+f8/an3THawfO0R83t R71ygriEBsvx53cD/usUXphJiExYhmCXDI4bAXPwaCC6A/RKHCzOV+9NNJIZ5ogV/G2S 8pMNSV0npLIeBpbOUEHn3w2Lv7JOVCHK4Mo7Lb441nKwpJMWrfARY6zuVzl7VvlyTVpk o5FJHb568dsbdKqo4qYHTORI/PV7TnK6QOZQAKs+TdqKiaqknDTJ2pjVh7juBL3ymxte s7qvx7rNBMzSWt+qUAl81q/365o9cPGOM9PszidR2lnfPx7Pae53gOLkuuPnOVrYPaaJ 8LpA== X-Gm-Message-State: AOAM531TiBqAZXUQvdiS6rN4P/kJZXVJh5IFP1GuyFWJuGJ5eN41nEQU mjxD0UROGXfb60BPVkiN9YEcfKwiqRRrPcX6xC4HIz0t X-Google-Smtp-Source: ABdhPJw6Iguinpi73NFk6y4PA5r3O3SWqlfgjlS/IpMTYJfhaP/U3isO/7jxuN9zItL2oBSF6taM8vbM+kKwBgXw5lg= X-Received: by 2002:a05:6808:218f:: with SMTP id be15mr5078376oib.75.1627733572302; Sat, 31 Jul 2021 05:12:52 -0700 (PDT) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply MIME-Version: 1.0 References: <9946c2eb-bb5c-a9c0-ced9-1ac269cd69a0@gmail.com> <6ecbf2d6-2c6f-3f66-5eee-f4766d5e5254@gmail.com> <24805.48814.331408.860941@tux.local> <5483630c-3cd1-bca2-0a6d-62bb85a5adc6@gmail.com> <96fc901a-2ce4-0ea0-0ed1-1c529145c0e9@gmail.com> <6102DB58.7040103@youngman.org.uk> <56d64f52-1b9a-1309-c720-06bb63c9f80a@iinet.net.au> <7a8c52c3-4c96-89ac-ace0-6eb4b8f1401f@iinet.net.au> <6104C897.5010505@youngman.org.uk> <7e6b56a2-917f-4dd6-3599-722bca5162ca@iinet.net.au> In-Reply-To: <7e6b56a2-917f-4dd6-3599-722bca5162ca@iinet.net.au> From: Rich Freeman Date: Sat, 31 Jul 2021 08:12:40 -0400 Message-ID: Subject: Re: [gentoo-user] [OT] SMR drives (WAS: cryptsetup close and device in use when it is not) To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset="UTF-8" X-Archives-Salt: db51e395-5b6d-4e19-ad93-d569277d8f8d X-Archives-Hash: c105245a900318b6786b07ffdc3c0e17 On Sat, Jul 31, 2021 at 12:58 AM William Kenworthy wrote: > > I am amused in a cynical way at disk manufacturers using decimal values ... > So, the disk manufacturers obviously have marketing motivations. However, IMO the programming community would be well-served to just join basically every other profession/industry on the planet and use the SI units. If you want to use GiB to measure things by all means do so, but at least stick the "i" in your output. You're not going to change ANYTHING by using SI decimal prefixes to refer to base-2 units. Everybody on the planet who isn't a programmer is already using SI prefixes, recognizes SI as the authoritative standards body, and most of the governments on the planet probably have the SI prefixes enacted as a matter of law. No court on the planet is going to recognize even the most accomplished computer scientists on the planet as speaking with authority on this matter. All sticking to the old prefix meanings does is confuse people, because when you say "GB" nobody knows what you mean. Plus it creates other kinds of confusion. Suppose you're measuring recording densities in KB/mm^2. Under SI prefixes 1KB/mm^2 equals 1MB/m^2, and that is why basically every engineer/scientist/etc on the planet loves the metric system. If you're going to use base-2 units for bytes and base-10 for meters, now you have all sorts of conversion headaches. The base-2 system only makes sense if you never combine bytes with any other unit. I get that programming tends to be a bit isolated from engineering and so we like to pretend that never happens, but in EVERY other discipline units of measure tend to be combined all the time, and it certainly happens in engineering real computers that don't use infinitely long tapes and only exist in CS textbooks. :) Just to combine replies: by "read-only" scrubbing I wasn't referring to using "-r" but rather just that the scrub wasn't repairing anything. A scrub operation will repair problems it finds automatically, and that would of course take a huge hit on SMR. I'd expect a scrub that doesn't encounter problems to perform similarly on CMR/SMR, and something that does a ton of repair to perform terribly on SMR. Your numbers suggest that the SMR drive is fine for scrubbing without errors (and if you have no mirroring/parity of data then you can't do repairs anyway). I'm guessing the drive was just busy while scrubbing, and obviously a busy spinning disk isn't going to scrub very quickly (that might be tunable, but if you prioritize scrubbing then regular IO will tank - typically you want scrubbing at idle priority). -- Rich