Xen CPU Use per Domain again

8 years ago I wrote a script to summarise Xen CPU use per domain [1]. Since then changes to Xen required changes to the script. I have new versions for Debian/Wheezy (Xen 4.1) and Debian/Jessie (Xen 4.4).

Here’s a new script for Debian/Wheezy:

#!/usr/bin/perl use strict;

open(LIST, "xm list --long|") or die "Can't get list";


Dedicated vs Virtual Servers

A common question about hosting is whether to use a dedicated server or a virtual server.

Dedicated Servers

If you use a dedicated server then you will face the risk of problems which interrupt the boot process. It seems that all the affordable dedicated server offerings lack any good remote management, so when the server […]

Server Costs vs Virtual Server Costs

The Claim

I have seen it claimed that renting a virtual server can be cheaper than paying for electricity on a server you own. So I’m going to analyse this with electricity costs from Melbourne, Australia and the costs of running virtual servers in the US and Europe as these are the options available to […]

Xen and Debian/Squeeze

Ben Hutchings announced that the Debian kernel team are now building Xen flavoured kernels for Debian/Unstable [1]. Thanks to Max Attems and the rest of the kernel team for this and all their other great work! Thanks Ben for announcing it. The same release included OpenVZ, updated DRM, and the kernel mode part of Nouveau […]

Starting with KVM

I’ve just bought a new Thinkpad that has hardware virtualisation support and I’ve got KVM running.


The Linux-KVM site has some information on using hugetlbfs to allow the use of 2MB pages for KVM [1]. I put “vm.nr_hugepages = 1024” in /etc/sysctl.conf to reserve 2G of RAM for KVM use. The web page notes […]

Virtual Hosting Features

I’ve just been setting up new virtual servers at Linode [1] and Slicehost [2]. I have previously written a review of both those services [3], based on that review (and some other discussions) one of my clients now has a policy of setting up pairs of virtual servers for various projects, one server at Linode […]

New Servers – a non-virtual Cloud [1] provides an interesting service. They have a cloud computing system that is roughly comparable to Amazon EC2, but for which all servers are physical machines (blade servers with real disks). This means that you get the option of changing between servers and starting more servers at will, but they are all physical systems […]

Dom0 Memory Allocation and X

I’ve previously written about memory squeeze problems in a Xen Dom0 when large amounts of memory were assigned to DomUs [1]. In summary the Dom0 would have problems if started with default options and the majority of the RAM was later assigned to DomUs, but if the memory of the Dom0 was limited by the […]

Red Hat, Microsoft, and Virtualisation Support

Red Hat has just announced a deal with MS for support of RHEL virtual machines on Windows Server and Windows virtual machines on RHEL [1]. It seems that this deal won’t deliver anything before “calendar H2 2009” so nothing will immediately happen – but the amount of testing to get these things working correctly is […]

Xen and Lenny

Debian GNU/Linux 5.0 AKA “Lenny” has just been released [1].

One of the features that is particularly noteworthy is that Xen has been updated and now works fully and correctly on the 2.6.26 kernel (see the Debian Wiki page about Xen for details [2]). This may not sound exciting, but I know that a lot […]