KVMdiskResizeOnline

qemu-kvm disk can be resized online by libvirt feature blockresize:

1) ... some lvextend here...

2)lvs --units k /dev/mapper/R10_HD10k_0-KVM_alcoma_DSQ_disk2
    LV                   VG          Attr       LSize         Pool Origin Data%  Move Log Cpy%Sync Convert
  KVM_alcoma_DSQ_disk2 R10_HD10k_0 -wi-ao---- 419430400.00k                                             

3) virsh # domblklist kvm_alcoma_dsq
Target     Source
------------------------------------------------
sda        /dev/R10_HD10k_0/KVM_alcoma_DSQ_disk1
sdb        /dev/R10_HD10k_0/KVM_alcoma_DSQ_disk2

4) virsh # blockresize kvm_alcoma_dsq --path /dev/R10_HD10k_0/KVM_alcoma_DSQ_disk2 --size 419430400
Block device '/dev/R10_HD10k_0/KVM_alcoma_DSQ_disk2' is resized