[Qemu-discuss] Content mismatch at offset 6577717248!

[Andrew Cagney]

I'm creating a bunch of VMs that share a copy-on-write disk image
using the sequence:

- create a raw disk image using virt-install:

fallocate -l 8G '/home/build/pool/swanfedorabase.img'
sudo virt-install \
    --connect=qemu:///system \
    --network=network:default,model=virtio \
    --initrd-inject=testing/libvirt/fedorabase.ks \
    --extra-args="swanname=swanfedorabase ks=file:/fedorabase.ks
console=tty0 console=ttyS0,115200" \
    --name=swanfedorabase \
    --disk path='/home/build/pool/swanfedorabase.img' \
    --ram 1024 \
    --vcpus=1 \
    --check-cpu \
    --accelerate \
    --location=Fedora-Server-DVD-x86_64-21.iso \
    --nographics \
    --noreboot \
    --hvm

- converting the raw image to .qcow2:

rm -f /home/build/pool/swanfedorabase.qcow2
sudo qemu-img convert -O qcow2 '/home/build/pool/swanfedorabase.img'
'/home/build/pool/swanfedorabase.qcow2'

- creating copies of the qcow master:

sudo qemu-img create -F qcow2 -f qcow2 -b
'/home/build/pool/swanfedorabase.qcow2' '/home/build/pool/east.qcow2'

- and finally attatch that to a VM

I'm finding that the final image in the clones can be corrupt (empty
files, checksum failures, ...); going back and booting the master vm
and everything checks out :-/

Any suggestions on how to track this problem down (or perhaps a better
way to do this?).

Andrew

Fedora release 22 (Twenty Two)
$ qemu-img --version
qemu-img version 2.3.1 (qemu-2.3.1-10.fc22), Copyright (c) 2004-2008
Fabrice Bellard