Надо увеличить диск в LVM машине:

mail ~ # LANG=POSIX fdisk -l
Disk /dev/vda: 17.2 GB, 17179869184 bytes
16 heads, 63 sectors/track, 33288 cylinders, total 33554432 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa34fb249
   Device Boot      Start         End      Blocks   Id  System
/dev/vda1            2048     2097151     1047552   82  Linux swap / Solaris
/dev/vda2   *     2097152    33554431    15728640   83  Linux
Disk /dev/vdb: 177.1 GB, 177066737664 bytes
16 heads, 63 sectors/track, 343088 cylinders, total 345833472 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/vdb doesn't contain a valid partition table

mail ~ # df -h
пєп╟п╧п╩п╬п╡п╟я▐ я│п╦я│я┌п╣п╪п╟           п═п╟пЇп╪п╣я─ п≤я│п©п╬п╩я▄пЇп╬п╡п╟пҐп╬  п■п╬я│я┌ п≤я│п©п╬п╩я▄пЇп╬п╡п╟пҐп╬% Cп╪п╬пҐя┌п╦я─п╬п╡п╟пҐп╬ п╡
rootfs                        15G         2.1G   13G           15% /
/dev/root                     15G         2.1G   13G           15% /
rc-svcdir                    1.0M          92K  932K            9% /lib64/rc/init.d
cgroup_root                   10M            0   10M            0% /sys/fs/cgroup
udev                          10M         148K  9.9M            2% /dev
shm                          491M            0  491M            0% /dev/shm
192.168.0.254:/usr/portage    28G         4.4G   23G           17% /usr/portage
/dev/vdb                     112G         103G  3.5G           97% /mnt/cyrus

в libvirt xml файле содержимое такое :

<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE 
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
  virsh edit mail
or other application using the libvirt API.
-->
<domain type='kvm'>
  <name>mail</name>
  <uuid>e3ac05d0-554b-6350-4b5c-d0839ab07aa8</uuid>
  <memory>2097152</memory>
  <currentMemory>1048576</currentMemory>
  <vcpu>2</vcpu>
  <os>
    <type arch='x86_64' machine='pc-1.0'>hvm</type>
    <boot dev='hd'/>
    <bootmenu enable='no'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/bin/qemu-kvm</emulator>
    <disk type='block' device='disk'>
      <driver name='qemu' type='raw'/>
      <source dev='/dev/gw/mail-root'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </disk>
    <disk type='block' device='disk'>
      <driver name='qemu' type='raw'/>
      <source dev='/dev/gw/mail-spool'/>
      <target dev='vdb' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </disk>
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <interface type='bridge'>
      <mac address='52:54:00:44:02:86'/>
      <source bridge='br0'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes'/>
    <video>
      <model type='cirrus' vram='3072' heads='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </memballoon>
  </devices>
</domain>

Как внести изменения, в диск чтобы виделись не 112гб , а весь размер?