Hyper-V R2 Dynamic Memory: over-subscription vs. over-commitment

This content is 14 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

There’s been a lot of talk about how Microsoft’s Dynamic Memory capability in Hyper-V R2 compares with similar features from VMware – including the pros/cons of each approach. Because that’s been so well-covered elsewhere, I’ll avoid it here (from the VMware perspective, check out Eric Gray (vCritical),  for Microsoft Ben Armstrong is your man and, for a completely unbiased and objective view… well, good luck finding one). I did see an interesting quote however from one of Ben’s TechEd sessions in New Zealand recently:

  • “Over-subscription is what airlines do by selling more seats than places in a plane.
  • Over-commitment is what happens when all those passengers actually show up to use their seat.”

[Ben Armstrong at TechEd New Zealand]

One of my fellow Virtual Machine MVPs, Ronald Beekelaar, extended this analogy and it seemed good to share it more widely…

There is nothing wrong with over-subscription – it happens in many real-world scenarios such as: public transport; libraries; Doctors’ surgeries; hospitals; utility companies; telephone systems; etc.  – and these work well (most of the time). The issues occur when all of the people that could actually use the service try to at the same time, at which time we have over-commited the service.

What do we do when we have over-commitment? We add more resources (run extra buses, add carriages to a train, add books to the library, open a new hospital ward, lay more telephone cables, etc.) – and in the world of virtualisation, we add one or more hosts and migrate some of the conflicting workloads away.


This content is 14 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

I recently spent a couple of weeks on holiday in Dorset with my family. Being August, the weather was best described as “variable” (May, June and September are the best months for good weather in England) but we had a few sunny days and, the on last couple of evenings, I managed to get out and take some pictures.

We were staying in Swanage, which is a pleasant seaside town (a bit run down but not too spoilt) but, because Swanage Bay faces east, it’s not the best place to take sunsets (and I’m not too great at getting out of bed for the dawn shift). I decided to try and catch the last of the golden hour, as the low sun reflected off buildings and boats but it wasn’t really working out – there wasn’t even any cloud interest (although the clear sky was great for our holiday, it’s not very interesting photographically!). I did, however, bump into a fellow photographer on the beach (Scott Howse), who provided me with some inspiration for a return visit the following evening.

Once the children were in bed, I sneaked out and dashed around trying to find a suitable location, snapping some quick shots as I pulled up on double yellow lines across the town but I was struggling to find the right location. As a last resort, I headed for a point half way around the bay, where I thought I might at least get some beach shots. As I pulled into a side road to park, an SUV approached from the opposite direction and headed for the same space. I could have nipped in front but I chose not to, shrugging my shoulders to indicate that the other driver could have the space, before driving on to find somewhere else to park.

As I walked back down the hill, I considered that perhaps giving up the space might result in some positive benefit to me – call it Karma if you like but I really didn’t expect to get large chunks of beach and a pier to myself for a whole 10 minutes or so! Admittedly, it was the evening on a bank holiday Monday, so lots of people would have been heading home, but I consider myself incredibly lucky to have captured the shots below with no-one else on the pier.

I settled down with my tripod and, taking Scott’s advice from the previous evening, I knocked down the ISO to my camera’s lowest calibrated setting, as well as making use of my Lee Filters ND grad to balance the bright sky with the foreground. A few minor tweaks in Lightroom (cropping, removing dust spots) and these are the resulting images.

Banjo Pier 2
Banjo Pier 3

Later this month I’m off to the Lake District for a long weekend dedicated to photography and, if I manage to capture images like these, I’ll be a very happy punter.

(The images in this post are ©2010 Mark Wilson, all rights reserved and are therefore excluded from the Creative Commons license used for the rest of this site.)

Upcoming events (including special #uktechdays) event

This content is 14 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

We’re having difficulties scheduling WSUG events right now. Without going into all the gory details, Microsoft’s funding for rooms, etc. is not available in the way that it has been in the past, so we need to find another way to do things…

Now that the summer holidays are over, I’d like to organise a “virtual” user group meeting, over Live Meeting – and have had some conversations with Microsoft about a session on “Azure for IT Pros” (how can we integrate our on-premise infrastructure with Windows Azure, etc.). Please leave a comment if you think this will be of interest.

In the meantime, I wanted to tell you about a Microsoft-hosted event that may be of interest, although it may also be a bit “developery” for some Windows Server admins.

In any case, Steve Ballmer will be the guest speaker at a special UK TechDays “Future of Cloud Development” event in London’s Docklands on 5 October.

The site has not gone live yet but you can registration on the event page or at 0870 166 6670, quoting event reference 9886 – you’ll also need the invitation code: 6D4723.

More details of the session content can be found below:

  • A lap around Windows Phone 7 (Mike Ormond) – In this session Microsoft will take a look at Windows Phone 7 and the developer ecosystem, from the capabilities and unique features of the platform to the development frameworks and tools you have at your disposal. Along the way they’ll build a simple application or two and explore how people can purchase your finished masterpiece.
  • A lap around the Windows Azure Platform (Eric Nelson) – Hear how the Windows Azure Platform provides a scalable compute and storage environment with Windows Azure, secure connectivity with Service Bus and Access Control Service, and a relational database with SQL Azure. Learn about these new services and see demos that show how to build applications that run in and take advantage of Microsoft’s new cloud platform.
  • We’re Not on XP Any More – A Windows 7 Application in 60 Minutes. (Mike Taulty) – In this code-only session Microsoft will use Visual Studio 2010 and any .NET assembly that we can beg, borrow, steal or even build in order to put together a simple, modern Windows 7 application from scratch using the journey to provide pointers on how your applications can shine by using features that Windows XP only dreamt about ( when it wasn’t dreaming of electric sheep in its world limited by 2 processor cores, 4GB of RAM and GDI based graphics).
  • Keynote: New opportunities and compelling experiences – Microsoft’s Chief Executive Officer, Steve Ballmer, will talk about new opportunities to deliver seamless experiences across many screens and a cloud, and why now is such an exciting time for developers
  • IE9 The Best Browser for Windows (Martin Beeby) – In this session Microsoft will use IE9 and a sprinkling of JavaScript and HTML5 to show you how to create an integrated and immersive experience maximizing the full power of your visitors Windows 7 PC.

[A version of this post also appears on the Windows Server User Group blog]

Jailbreaking does not equal piracy

This content is 14 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

A couple of night ago, Mrs. W was watching Channel 4 News as they ran a lengthy package on “how iPhone jailbreaking is fuelling app piracy“.  The trouble is that Channel 4’s Benjamin Cohen seems to have confused jailbreaking (the process of allowing non-authorised applications to be installed, rather than using Apple’s walled garden approach) with piracy (copying, distributing and installing applications against the wishes of the software creator).

I have a jailbroken iPhone – and it’s not so that I can pirate apps.  Frankly, if you’re a teenager who’s made a hundred grand in your bedroom from writing iPhone games, well done and good luck to you.  But don’t complain when there are 20% more people running your software than paid for it – you should have thought more how you were going to control the use of your app.

The reason my phone is jailbroken is simple – I want to use an alternative music player (Spotify) whilst I’m tracking my exercise progress (with Runkeeper).  That requires multi-tasking and Apple doesn’t allow multitasking on my iPhone 3G.  In a sense that’s OK – the IOS4 operating system that allows multitasking seems to need more powerful hardware (so why it’s available for the 3G is anyone’s guess) but I can make it work using a simple jailbreak and an application called Backgrounder.

Basically, Apple charged me a lot of money for a desirable piece of computing hardware and is their business model relies on increasing obsolescence so that I buy a new device.  If I have the technical ability to make that hardware do more for me and avoid buying a new phone, then why shouldn’t I?  I haven’t installed any unlicensed software, I’m not putting additional load on my mobile provider’s network, and the hardware is out of warranty already.  You could even argue that, by not buying a new iPhone, I’m making better use of my legacy computing device and doing my bit to save the planet!

It’s kind of analogous to the guys who “mod” their cars to move away from the manufacturer’s specifications.  Sure, they won’t get warranty support, but if they get a few more horsepower or whatever it is they are looking for out of their vehicle, that’s up to them.

So, back to the point – whilst it may be possible to use jailbroken phones for piracy, jailbreaking does not equal piracy.  If I was so inclined, I could run unlicensed copies of Windows on my PC, or install an unlicensed copy of Adobe Photoshop on my Mac, but I don’t hear national broadcasters suggesting that all Windows or Mac users are software pirates.