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=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 77E0FC433DF for ; Fri, 31 Jul 2020 03:36:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53BB4208E4 for ; Fri, 31 Jul 2020 03:36:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=colorremedies-com.20150623.gappssmtp.com header.i=@colorremedies-com.20150623.gappssmtp.com header.b="uyKY8BtQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731302AbgGaDgT (ORCPT ); Thu, 30 Jul 2020 23:36:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730820AbgGaDgT (ORCPT ); Thu, 30 Jul 2020 23:36:19 -0400 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9131DC061574 for ; Thu, 30 Jul 2020 20:36:18 -0700 (PDT) Received: by mail-wm1-x334.google.com with SMTP id k8so7993313wma.2 for ; Thu, 30 Jul 2020 20:36:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=colorremedies-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=AdQJyJqpFN2fR/l7hckq15lT8jtEq5VWWhRVFYg0P/Q=; b=uyKY8BtQdlmEneE0oQsNDF4E/t+y1wSvB2KqCV9g0bDVt+jeoylYPutoHkfJf82ars rnXLnVvF9aMqhiOUvJ2N9gvo9f6sFg3rJJ8cIZscdRvt5DhsILRWM1KZJq0Bgvlz2OfF s1+a+MgXOF9Qq6an90YhmpxBmVco1z2j4aFYU7bJb966sT1X/pAgI+IiiVBsaLdgn+OB kViajbiUci5va/JggfAyBpMMzLEdhQewMi9t4VOIjsXQ9MGR5ogjHON+mG1XulkDpH/c sLxlFWfSN/AVgxFmrdQ8PGd1fI2Twr5ZkM2TUGRoOCxPQcco8c0ACRkNrY6QJ3g/PWCL 7IYg== 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:cc; bh=AdQJyJqpFN2fR/l7hckq15lT8jtEq5VWWhRVFYg0P/Q=; b=TJFmmBOOFciJOphfjhXi1En47VOnVYUs7AnAfBBW4Ib7rovlz4NmKPhHTWujs0xQpJ Je3ZwmqzAMFV5nZGgk3Y2WuUCEp/uhTG5azBtrWRSO7sY7vzUBKGVQ7s1qrUghNZmRUh 5h7/4uI7+EA42ED0Oc7fCu0wEtMB4VxT+ntjklQgPonMPyHaXPaFCUa8KOQ1q1iLPAr1 qGYnoNyGD8BjzhnKdyK29dgbTzyTLxHgkYn0SOwiQFgI/U3SyIRby2ifFW1fU+S5jybJ 6QzS62DyB8bjqK+jZQbPIlH/ZMfO134Nqq26g4qt0KrBuCJHo3sg3X+auw7Mw21/M3Cg /Jng== X-Gm-Message-State: AOAM531ZDFRN0KqddJNTG932r+Hnma+e16XdL03WaIZnH8yl6lt7/Xwa qV5ifu81s6fkM17yHKnfIQHQsXWIu00hWlQboF7XbrDv X-Google-Smtp-Source: ABdhPJz9Qw7qNFKxCvVtDz2hMO36sMOnbDhn+m+5AzmrLYBLQIQtvvuzuzGeyVtp1DcClegCfqY6cIAzjAiynxbwMws= X-Received: by 2002:a1c:a756:: with SMTP id q83mr1840353wme.168.1596166575610; Thu, 30 Jul 2020 20:36:15 -0700 (PDT) MIME-Version: 1.0 References: <20200731001652.GA28434@dcvr> <20200731032212.GA21797@dcvr> In-Reply-To: <20200731032212.GA21797@dcvr> From: Chris Murphy Date: Thu, 30 Jul 2020 21:35:58 -0600 Message-ID: Subject: Re: raid1 with several old drives and a big new one To: Eric Wong Cc: Btrfs BTRFS Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Jul 30, 2020 at 9:22 PM Eric Wong wrote: > > Chris Murphy wrote: > > When one of the 2TB fails, there's some likelihood that it'll behave > > like a partially failing device. Some reads and writes will succeed, > > others won't. So you'll need to be prepared strategy wise what to do. > > Ideal scenario is a new 4+TB drive, and use 'btrfs replace' to replace > > the md concat device. Due to the large number of errors possible with > > the 'btrfs replace' you might want to use -r option. > > If I went ahead with btrfs alone and am prepared to lose some > (not "all") files; could part of the FS remain usable (and the > rest restorable from slow backups) w/o involving LVM? > > I could make metadata (and maybe system chunks?) raid1c3 or even > raid1c4 since they seem small and important enough with ancient > HW in play. Yes. I'm not sure whether it will mount rw,degraded if 2 devices are missing though, it might insist on read-only. -- Chris Murphy