Red Hat Bugzilla – Bug 165585
LVM2 snap shots corrupt MD-RAID1
Last modified: 2007-11-30 17:11:11 EST
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Description of problem:
After creating a snap shot of the root LVM2 volume on a MD-RAID1 IDE drives, common commands fail with "cannot execute binary". This happens when trying to use commands like tar or mke2fs or even top and clear, after mounting the snap shot.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Create fresh install of FC4 onto an IDE MD-RAID1 drive set. Drive configuration like this: /dev/md0 = /dev/hda1 + /dev/hdc1 (100MB) EXT2 (/boot) and /dev/md1 = /dev/hda2 + /dev/hdc2 (200GB) LVM. Create / during install of 4096MB as /dev/vg0/root. Reboot after install and login as normal root user.
2. Create a Backup Volume: lvcreate -L20GB -n /dev/vg0/Backup prepare as EXT3 and mount this volume, /mnt/Backup.
3. Create a snap shot of active root volume: lvcreate -L200M -s -n snap /dev/vg0/root and mount this volume, /mnt/snap.
4. Now try to backup up /mnt/snap to /mnt/Backup: tar -czf /mnt/Backup/root.tgz /mnt/snap
Actual Results: As soon as you try to run tar, you will get the error "cannot execute binary". Most every command will begin to fail, including "shutdown -h now" with the same error.
Expected Results: Normally the backup of a snap shot using tar should run as expected. It is good practice to backup before major system changes and LVM snap shots is a great way to do this.
This issue does not occur in non-MD-RAID IDE systems. I do this all the time on single drive systems including my laptop. I think there must be some conflict with the way LVM freezes the blocks that screws up MD RAID.
*** This bug has been marked as a duplicate of 159749 ***