From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f42.google.com ([209.85.214.42]:38215 "EHLO mail-it0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756816AbcILOvO (ORCPT ); Mon, 12 Sep 2016 10:51:14 -0400 Received: by mail-it0-f42.google.com with SMTP id n143so10029626ita.1 for ; Mon, 12 Sep 2016 07:51:13 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1771908.LWBdy5fQ5X@merkaba> <3e8e686c-9c42-a1e1-a0ac-9eb27208360d@gmail.com> From: Chris Murphy Date: Mon, 12 Sep 2016 08:51:12 -0600 Message-ID: Subject: Re: Small fs To: Henk Slager Cc: "Austin S. Hemmelgarn" , Martin Steigerwald , Imran Geriskovan , linux-btrfs Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Mon, Sep 12, 2016 at 8:09 AM, Henk Slager wrote: >> FWIW, I use BTRFS for /boot, but it's not for snapshotting or even the COW, >> it's for DUP mode and the error recovery it provides. Most people don't >> think about this if it hasn't happened to them, but if you get a bad read >> from /boot when loading the kernel or initrd, it can essentially nuke your >> whole system. I run BTRFS for /boot in DUP mode with mixed-bg (because I >> only use 512MB for boot) to mitigate the chance that a failed read has any >> impact, and ensure that if it does, it will refuse to boot instead of >> booting with a corrupted kernel or initrd. > > Suppose kernel and initrd are on a BTRFS fs with data, metadata and > system all single profile. Will a bootloader then just continue > booting up a system even when there are csum errors in kernel and/or > initrd files? Suppose the bootloader is grub2. I"m wondering the same thing. I don't know if GRUB's Btrfs code checks for csum matches, and on error whether it knows to retry from some other block group. -- Chris Murphy