Comment 31 for bug 1317491

# Testing Bigger Merge

inaddy@(kvm02):~$ sudo qemu-img info --backing-chain /var/lib/libvirt/images/guest.1487880011
image: /var/lib/libvirt/images/guest.1487880011
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 196K
cluster_size: 65536
backing file: /var/lib/libvirt/images/guest.1487879972
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false

image: /var/lib/libvirt/images/guest.1487879972
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 466M
cluster_size: 65536
backing file: /var/lib/libvirt/images/guest.1487879587
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false

image: /var/lib/libvirt/images/guest.1487879587
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 3.6M
cluster_size: 65536
backing file: /var/lib/libvirt/images/guest.1487877813
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false

image: /var/lib/libvirt/images/guest.1487877813
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 2.9M
cluster_size: 65536
backing file: /var/lib/libvirt/images/guest.qcow2
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false

image: /var/lib/libvirt/images/guest.qcow2
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 5.0G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false

# Writing to guest

inaddy@(guest):~$ dd if=/dev/zero of=./teste bs=1M count=1024
^C465+0 records in
465+0 records out
487587840 bytes (488 MB) copied, 8.74541 s, 55.8 MB/s

# Testing a bigger merge (several snapshots at once)

inaddy@(kvm02):~$ virsh blockcommit --domain=guest --path=/var/lib/libvirt/images/guest.1487880011 --base /var/lib/libvirt/images/guest.qcow2 --top /var/lib/libvirt/images/guest.1487879972 --wait --verbose
Block Commit: [100 %]
Commit complete

# There are only 2 snapshots at the end:

inaddy@(kvm02):~$ sudo qemu-img info --backing-chain /var/lib/libvirt/images/guest.1487880011
image: /var/lib/libvirt/images/guest.1487880011
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 1.1M
cluster_size: 65536
backing file: /var/lib/libvirt/images/guest.qcow2
backing file format: qcow2
Format specific information:
    compat: 1.1
    lazy refcounts: false

image: /var/lib/libvirt/images/guest.qcow2
file format: qcow2
virtual size: 30G (32212254720 bytes)
disk size: 5.4G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false