From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joel Young Subject: RAID 0 of Two RAID 5s Stays Up When Component RAID fails Date: Thu, 14 Mar 2013 01:33:52 +0000 (UTC) Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids What should the output be for the following sequence: dd if=/dev/zero of=i1 bs=1M count=100 dd if=/dev/zero of=i2 bs=1M count=100 dd if=/dev/zero of=i3 bs=1M count=100 dd if=/dev/zero of=i4 bs=1M count=100 dd if=/dev/zero of=i5 bs=1M count=100 dd if=/dev/zero of=i6 bs=1M count=100 losetup /dev/loop1 i1 losetup /dev/loop2 i2 losetup /dev/loop3 i3 losetup /dev/loop4 i4 losetup /dev/loop5 i5 losetup /dev/loop6 i6 mdadm --create /dev/md0 --level=5 --raid-devices=3 \ /dev/loop1 /dev/loop2 /dev/loop3 mdadm --create /dev/md1 --level=5 --raid-devices=3 \ /dev/loop4 /dev/loop5 /dev/loop6 mdadm --create /dev/md2 --level=0 --raid-devices=2 \ /dev/md0 /dev/md1 mdadm /dev/md0 --fail /dev/loop0 mdadm /dev/md0 --fail /dev/loop1 mdadm --detail /dev/md0 mdadm --detail /dev/md2 dd if=/dev/zero of=/dev/md2 bs=1M Shouldn't /dev/md2 be failed at this point? Shouldn't the dd get an error? No error was reported. /dev/md2 is writable. Where are the writes going? What am I missing? This is running on fedora 18. We saw the problem with production arrays on fedora 17. mdadm version: mdadm - v3.2.6 - 25th October 2012 kernel: 3.7.9-201.fc18.x86_64 Thanks, Joel