Tag : Virtualisation

How to resize a VMDK using Qemu tools

It is possible to resize a VMware .VMDK file without using the VMware tools.

The QEMU disk image utility comes with qemu-img a tool which allows you to convert virtual disk formats.

To resize a VMDK using qemu-img

# First convert the vmdk to raw format
# NB. Make sure you reference the actual disk image and not the .vmdk descriptor file
qemu-img convert linux-flat.vmdk linux.raw

# Extend the vmdk using dd. 
# Here we are extending the disk to 16G using dd. The resulting file will be sparse
dd if=./linux.raw of=./linux-16G.raw BS=1M seek=16384 oflag=append ...

— Andrew

The Joy of OpenVZ virtualisation

We are huge fans of OpenVZ container level virtualisation. Although we're quite puzzled as to why it is not more popular.

What is OpenVZ you ask?

OpenVZ is operating system-level virtualization based on a modified Linux kernel that allows a physical server to run multiple isolated instances known as containers, virtual private servers (VPS), or virtual environments (VE). The preferred term these days is container. Containers are sometimes compared to chroot or jail type environments but containers are really much better in terms of isolation, security, functionality, and resource management.

Why we use OpenVZ

In a nutshell: Because a ...

— Andrew

Disabling NTPD in FreeNAS 8

If you're running FreeNAS 8 under VMware, Xen or KVM, then you'll probably want to disable ntpd. To do this you'll need to ssh into your FreeNAS box as root and run the following commands.

mount -uw /
vi /conf/base/etc/rc.conf

Change ntpd_enable="YES" to ntpd_enable="NO" and ntpd_sync_on_start="YES" to ntpd_sync_on_start="NO".

Then reboot and you should find that ntpd has been disabled. This should help eliminate any time jitter issues when running ntpd on a virtualised environment.

— Andrew

How to Virtualize Windows 2008 SBS with Xen on CentOS 5

Installing Windows SBS 2008 as a Xen Fully Virtualized guest using the XEN hypervisor on CentOS 5 is fairly straight forward.


Starting off we need a CentOS 5 server with at least 4GB of free RAM and enough hard disk space to support SBS. The processors must support x86 Virtualization either Intel VT or AMD V. Virtualization must also be enabled in the system BIOS. If you server supports Hyper-threading you may want to turn it off, as this might improve performance with a Windows 2008 VM. The Xen hypervisor presents the individual hyper-threaded cores as physical cores to ...

— Andrew

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