Setting Up LVM Backed Xen DomU

LVM volumes as backing for DomU’s file system is an appealing solution to Xen VBD. LVM volumes can dynamically grow/shrink and snapshot. These features make it simple and fast to duplicate DomU and adding storage to DomU. Creating LVM-backed Xen DomU is introduced in this post.

Create LVM-backed VBD

Suppose we have a LVM volume group for Xen now: vg_xen.

Let’s create a logical volume of size 20GB named ‘vm-10.0.0.123′ for the VM we will create:

# lvcreate -L20480 -n 'vm-10.0.0.123' vg_xen

Please refer to Creating LVM Volume Group for setting up LVM volume group.

The profile for LVM-backed DomU

Then we can create a profile for LVM-bakced Xen DomU using the LVM logical volume we create above:

name="lvm-backed-domainu"
vcpus=2
memory=2048
disk=['phy:mapper/vg_xen--vm-10.0.0.123,xvda,w']
# disk=['phy:vg_xen/vm-10.0.0.123,xvda,w']
vif=['bridge=eth0']
bootloader="/usr/bin/pygrub"
on_reboot='restart'
on_crash='restart'

or for installing a new DomU:

name="F12INSTALL"
vcpus=2
memory=2048
disk=['phy:mapper/vg_xen--vm-10.0.0.123,xvda,w']
# disk=['phy:vg_xen/vm-10.0.0.123,xvda,w']
vif = [ 'bridge=eth0' ]
kernel = "/lhome/xen/f12install/vmlinuz"
ramdisk = "/lhome/xen/f12install/initrd.img"
on_reboot = 'restart'
on_crash = 'restart'

The virtual machine’s name is “10.0.0.123″, memory is 2G, CPU number is 2, VBD is LV /dev/mapper/vg_xen/vm-10.0.0.123. The “disk” line specifies that we will use logical volume vm-10.0.0.123 in volume group vg_xen for this DomU’s VBD.

Then we can install operating system in the DomU. Please refer to the “Install Fedora 12 Linux via Internet” section in:

Setting Up Stable Xen DomU with Fedora: Unmodified Fedora 12 on top of Xenified Fedora 12 Dom0 with Xen 4.0

for installing Fedora 12 in Xen DomU.

For more tutorials about Xen, please refer to Xen Solution.

Update history:
Sep. 28, 2010. Add how to set up LVM volume group.
Jul. 16, 2011. Specify the section for how to install Fedora 12.