We’re proud of our blogs and hope you find them both interesting and informative. And we’re very pleased now to have been included in Online IT Degrees’ Top 100 Blogs for the industry.

You can find us in the “Top IT Industry Company Blogs” category with the likes of Digg, DELL and the Windows 7 team – which is very nice indeed.

Our blogs are important to the way we work as a company. They allow you to see what we’re interested in, and through them we can give you our take on what’s happening in the world of ISPs and the wider Internet.

http://onlineitdegrees.org/top-100-it-industry-blogs/

Having used PHP for a number of years to build a career and pay the bills, it feels particularly satisfying to contribute something back to the project. Also, those people making significant contribution may apply for a $username@php.net email address which looks cool on a business card!

With the recent release of PHP5.3RC2, the main focus is on improving code coverage for the 5.3 branch.  PHP core developer Scott MacVicar started the day with an introduction on how-to compile from source as well as run the existing tests. After pizza, we got down to the business of writing tests, starting with a simple example which I’ll run through…

First, download the latest 5.3 snapshot from snaps.php.net and extract it.  NorthWestUG were only focusing on testing the Standard PHP Library (SPL) so we disabled all the extensions to speed up the compilation time. If you’re interested in other extensions, use the appropriate switch to enable it – see ‘./configure –help | less’ for details. Note: you may need to install ‘build-essentials’, ‘ltp’ and ‘gcov’ packages before performing the following step.

tar zxvf php5.3*
cd php5.3*
./configure --disable-all --enable-gcov && make

Once complete, you should now have your compiled PHP CLI binary in sapi/cli/php. Lets test it,

$ sapi/cli/php -v
PHP 5.3.0RC2 (cli) (built: May  9 2009 19:48:19) (GCOV)
Copyright (c) 1997-2009 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2009 Zend Technologies

To run all the existing tests, approximately 5700, run ‘make test’.  To generate a code coverage report run ‘make lcov’ and open lcov_html/index.html to see the results.  Both these commands also accept a ‘TESTS=’ argument which is useful for testing individual directories and files when writing new tests.  For example, to only run the SPL tests, use ‘make test TESTS=ext/spl/tests/’. Now lets create our own test.  For this example, we’ll check that PHP can do basic addition.  PHP test files have a .phpt extension and consist of several sections.  Every test must contain TEST, FILE and EXPECT sections.

• TEST – a meaning description of the test
• FILE – your test code
• EXPECT – what the expected outcome of FILE is

There are many other sections however, CREDITS is common and completing this will get your name/email address into CVS.  Refer to the reference manual and QA PHP site for guidance. Here is the example test that Scott used (the new line at the bottom of the test is important!),

--TEST--
Check that PHP can count
--CREDITS--
Your name/email address
--FILE--
<?php
echo 10 + 10;
?>
--EXPECT--
20

Save the file using the .phpt extension and run the test, ‘make test TESTS=/path/to/test/filename.phpt’.  If for some reason the test fails a number of output files are created in the same directory as the test.  The most useful is the .diff file, this records the test’s actual output against what was expected. Assuming the test works as expected you get something like,

=====================================================================
PHP         : /path/php-5.3.0RC2/sapi/cli/php
PHP_SAPI    : cli
PHP_VERSION : 5.3.0RC2
ZEND_VERSION: 2.3.0
PHP_OS      : Linux - Linux work-laptop 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009 i686
INI actual  : /path/php-5.3.0RC2/tmp-php.ini
More .INIs  :
CWD         : /path/php-5.3.0RC2
Extra dirs  :
VALGRIND    : Not used
=====================================================================
Running selected tests.
PASS Check that PHP can count [/path/to/test/filename.phpt]
=====================================================================
Number of tests :    1                 1
Tests skipped   :    0 (  0.0%) --------
Tests warned    :    0 (  0.0%) (  0.0%)
Tests failed    :    0 (  0.0%) (  0.0%)
Expected fail   :    0 (  0.0%) (  0.0%)
Tests passed    :    1 (100.0%) (100.0%)
---------------------------------------------------------------------
Time taken      :    0 seconds
=====================================================================

Now we know how-to write basic tests, we need to find some real code to test.  PHP’s gcov site reports all untested code in red, so just pick a section and write a test for it. Once the test passed, re-run the code coverage report to ensure the expect line(s) is now green. When you’re happy with the test follow the what to do next instructions and submit it to the QA mailing list for review. It’s preferable to submit tests in batches rather then by drip-feeding them as the tests will be reviewed by the QA team, run on multiple OSes, hardware as well as committing to the 5.2, 5.3 and HEAD.

Thanks to iBuildings for sponsoring the event, Salford University for use of their facilitiess, Lorna Mitchell for organising the event, Scott for his mentoring and patience and to everyone that turned up and wrote some tests.  Currently NorthWestUG is in the lead with 95 tests!  All the tests created by the NorthWestUG can be found here.

Credit to Lorna Mitchell for the photos.  The full set is available here.

After reading Matt’s Twitter blog that he published a couple of weeks ago, I thought I’d take the opportunity to write a follow-up piece about my own experiences with the increasingly popular micro-blogging cum social networking service of the moment.

What I found particularly interesting about Matt’s blog were some of the comments that readers had left. Whilst there aren’t many, what is evident from these comments is something that I’ve noticed on a much larger scale when chatting to friends, family and work associates about the new social networking phenomena – You either love it, or you hate it!

It wouldn’t be the first time that I’ve seen this love/hate separation either. I remember there being a similar apprehension and reluctance to get involved when Facebook was still in it’s early days. Nowadays though, with more than 200 million users worldwide, it’s unusual to come across a person who *hasn’t* got a profile on the social networking behemoth. Will we see the same take up and general acceptance of Twitter as a social networking medium? A market research company called Nielsen Online have already published figures showing that Twitter take up in the UK grew by a massive 1,689% from February 2008 to February 2009 alone – That’s an estimated 1.78 million UK adopters!

I have to admit that I’m one of Twitter’s admirers. I’ve been well and truly sucked in and find it an extremely useful tool as both a source of news and as a real-time search engine. Let me provide you with an example of the latter:

Back in January, Google experienced a problem that caused all search results to be flagged as malware. I happened to be online when this happened and wondered whether or not it was a problem at my end or something that was affecting other users too. The problem was only evident for a short period of time, but whilst it was happening there was no acknowledgement of the problem’s existence on Google’s blog, neither did a Google search return any similar reports of problems. It was at this point that I turned to Twitter’s search API. By entering the search term ‘google’ I knew immediately that it wasn’t just me experiencing problems as there were countless other reports on the ‘Twittersphere’ from users having exactly the same problem as.

That’s one of the things I like about Twitter, there’s no ‘proper’ way to use it and different people use it in different ways. I use my personal account to keep in touch with my friends, keep up to date with the latest news and discover new and entertaining stuff on the web. On the other hand, I use Plusnet’s Twitter account to offer support to our customers, post service announcements and promote the company brand.

Whether you love it or hate it Twitter seems to be eveywhere you look. It’s in the papers, it’s getting parodied, celebrities are getting in on the act and there’s even a fan club to show appreciation for the loveable (if not slightly frustrating) ‘fail whale’ that appears when Twitter’s servers are under load!

YouTube have recently added a Twitter button to their video clips and Vodafone have recently announced that they’ve started offering a free SMS service for Twitter users in the UK (something that has been available in the states since the social networking site’s inception, but was withdrawn for users this side of the pond last year due to the ‘high costs of mobile text messaging in the UK’ ).

Whichever way you look at it, it seems like Twitter’s here to stay. One thing that does remain unclear though is what the future holds for the micro-blogging phenomena. After all, it costs money to run a service like Twitter and one has to question what revenue, if any, the site brings in. Last month there were claims that Twitter may soon start charging for corporate use and there was even speculation at one point that Google were looking to buy the company (which some might argue isn’t a great idea). In a recent blog post, Twitter founder Biz Stone posted that “…we hope to begin iterating on revenue products this year.” In the same piece however, he also goes onto say “…whatever we come up with, Twitter will remain free to use by everyone—individuals, companies, celebrities etc.” – I’ll leave it to you the reader to make of that what you will.

So there you have it, love it or loathe it I don’t think we’ve heard the last of Twitter and I can only see it increasing in popularity as the year progresses. If you’re already using Twitter then make sure you visit our page and follow Plusnet. If you’re not using Twitter then what are you waiting for? You never know, you might actually like it!

.

Bob Pullen
Plusnet Comms Team

While I’m getting pre-holiday giddiness, lets see what everyone else has been up to.

Bob from Comms

We’ve all been pretty darn occupied on the Comms Team today.

I’ve been drafting an email on the recent closure of our wi-fi service, and been knee-deep in documentation on some of the up and coming architectural improvements & enhancements that we’ll making to our email platform.

Chris and Matt have had their work cut out reacting to today’s data-centre outage and the problems we had with the phones over in CSC South Africa. Between them, they’ve also both managed to keep on top of the usual flow of change control reviews.

Mand’s been testing some of the content and coding changes for the launch of some new special offers tomorrow as well as making sure the CSC know what to expect.

In addition to all of that, we’ve even managed the odd forum and Usenet post too!

As opposed to a random link today, I thought I’d go with a poll. I had a moment of realisation yesterday whilst tapping away at my keyboard that I *never* use the right-hand shift key. Now if I’m completely honest, I’ve always thought this to be the expected behaviour for a typical right-handed typist. As I thought about it more though, it dawned on me that there are ergonomic reasons for having two shift keys and it’s probably how you’re ’supposed’ to type anyway? I decided to try using the right-hand shift key for certain key combinations and it all started to make sense. Thinking I must have been denying myself the luxery of this key for all these years I glanced up and asked the question of the others around the table…

To my surprise I wasn’t mocked and jeered. Far from it, turns out I’m not alone because everybody else around the table also neglected to make any use whatsoever of this key (which I must say is remarkably clean compared to the others on my keyboard!).

So how’s about it. Do you use the right-shift key, the left-shift key or both? Perhaps you’ve some other novel way of getting your keyboard to output upper case letters?

Why not let us know by filling out this poll.

Jake next from the CSC

Good Wednesday afternoon to you all from Jake in the CSC Tech with today’s top 5.

1. Fault update – When a customer has a fault, our faults team do endeavour to keep user’s up to date via calls and text messages. But sometimes when you’re Internet’s down you just feel helpless and because you can’t follow the ticket status online you need to call in. Completely understandable.

2. Router configuration – When you’re setting up a new router for the first time or it’s your first time on broadband it’s easy to get stuck, and we’ve as usual had a lot of calls on this today. The main thing is the realm at the end of the username, if you don’t know it you don’t know it, and for reference it’s username@plusdsl.net )
3. Email configuration – Usually part two of setting up your broadband, there’s a lot of usernames to remember and variations of said username which need using when first setting it all up, and then there’s also the mail servers. Folks need a quick help with these and are almost always well away after that.
4. Sales calls – Always a sign we’re doing something right when Sales features in the top 5. We’ve got loads of exciting things that have happened recently with our Broadband packages and there’s a lot of interest. The Essentials option is proving popular with our lighter broadband users and there’s a lot of interest in upselling to for Home Phone
5. Order Updates – People twitching to get online, can’t blame them, and again when you’ve not got the Internet you can’t follow progress online. A quick check on our BT system and people have an idea of when an order is likely to complete.

That’s all from the CSC today, thanks to everyone who’s called in and kept us busy – we’ve just taken our 1300th call of the day, as of 16.23!

QA regular Catherine closes the day. Do you think the rest of her team should help her out with these?

I know we say we’re busy too much, but today really has been worthy of the word. A lack of personnel due to illness and rollouts, along with some last minutes checks on a bunch of exciting things we’re rolling out tonight, has made for a rather hectic day. Of course, despite our facilities managers best efforts, the air con is still broken so it is still incredibly warm, particularly on pod QA. Ah well, all in a day’s work I’ve been on a couple of projects which need to stay under wraps for now, and fitting in some problems from our Polish colleagues where I can. Gavin has been working on our mail platform and picking up various bits and bobs too. Gary has been…unusually quiet, actually. Although he just started singing the ‘It’s getting hot in here’ song. Hmm. Matt 1 rolled out the changes for our wifi decommissioning changes last night, so he’s been at home all day. Alright for some. Nigel and Paul have been efficiently managing the aforementioned last minute checks and fitting in various bits of staging work as well. It’s Paul’s first overnight roll so wish him luck! We’ve also been helped by Mark and Mand from upstairs – thanks! Finally Matt 2 has been doing some testing in the middle of his burgeoning mangerial responsibilities and telling us about a ball of kittens he saw somewhere. Awww…

STOP PRESS: I’ve just heard that apparently the aircon will be fixed on Friday!

—

Woot! Working Aircon!

Well, that all from us today!

The story of unpacking and first use gets picked up on the Amnesia Blog.

The question will be how long it takes for these to become common in public spaces. If you’re a waiter or waitress, maybe you will be feeling a little concerned right now?

Ian

Crossloop combines the power of WinVNC with the security of SSL.  Connecting to a central service, connectivity between users is setup transparently to both sides – somthing taken care of by the  Crossloop servers.  The steps are really simple…

• User runs Crossloop
• User notes unique connection number
• User sends unique connection number to helper (either via IM or over the phone)
• User clicks ‘Connect’

The helper side is just as simple

• Helper runs Crossloop
• Helper enters connection number
• Helper clicks ‘Connect’

Both sides then establish the SSL tunnel over which the session traffic will be routed, to help prevent man-in-the-middle style attacks or discovery.  Then, when the tunnel is setup, WinVNC launches with the remote display on the Helpers PC.  Very cool.

But the fun doesn’t stop there.  What if you don’t have a family geek?  Do you steal a suitably pasty faced yoof from the local supermarket?  Thankfully there is an army of Crossloop members sat there just waiting for your cry for help.  They’ll help you whatever your problem, and they’ll do it for free.  Yes, you heard me, free.  Altruism at its best.  The singular drawback is that its WinVNC component still, sometimes, gets caught by the most stringent anti-malware applications which kinda breaks the whole process – frustrating as you don’t have access to the user’s PC in order to carry out the install to gain access to the user’s PC.  In most cases, adding the application to your anti-malware’s whitelist BEFORE running it will fix that little problem – adding it after is akin to closing the gate after the horse has bolted, WinVNC will already have been quarantined.

Check out these links, they show Crossloop in action.

http://crossloop.typepad.com/bringing_people_closer/2007/12/crossloop-raise

http://www.youtube.com/watch?v=QzbcuiMiwX0

Quite frankly, Crossloop is the best remote desktop app I’ve used…  It blows RDP away for the obvious reasons, but more importantly as a user you can have a high level of confidence that the guy on the other end of the connection is a good guy, and that your problem will be sorted out.

–
Disclaimer: Crossloop is an external application. PlusNet provides no guarantees as to its functionality, or warranty for any damage that using it may cause.

Although there are probably more reasons if you care to look into it for a specific situation I am discussing three here:

• Maximises hardware utilization
• Easier to support
• Enables rapid (or agile) deployment

Maximise Hardware Utilization

In an ideal world, applications should be coded to run in the multi-threaded CPU world that is rapidly becoming the norm, and handle the resource management without any intervention from the hardware. This is not the case of course, with some applications being CPU bound, single threaded or unable to utilise all the available memory on a server.

This is where virtualisation can help you out. You can effectively make a single piece of hardware that would normally run at very low load handle multiple instances of an application and therefore better utilise the resources available. This doesn’t mean you should run your hardware at 100% CPU utilisation, far from it in fact. Different applications may become unstable, or start to display very high latency as the hardware is loaded. Determining the cut-off point would be application specific and only careful testing and monitoring would allow you to gain optimal use of hardware.

There is also the danger of over virtualising for the sake of it. As soon as you define a service level against a platform you need to be able to maintain it, and the advantages of n+1 redundancy, and physical separation, come into play.

To take an example here from the PlusNet network, the mail platform is split across two sites on multiple machines with the data replicated between them. We could get all the functionality onto a handful of very powerful machines, but then a single (and always inevitable) hardware failure would result in a massive customer impact.

Maintaining this balance between service levels and your other savings is the trick here.

Ease of Support

This is another one that is often used as a reason to embark down the path of virtualisation. There are, however, a few gotchas so look out for.

The main one is that you will actually end up with more ’servers’ to maintain. Each virtual machine is managed, monitored and maintained exactly as if it was a separate physical server. On top of that you also have the underlying host for the virtual machines to look after. This also means there is another layer of complexity in your systems (read another thing to go wrong), and also another chunk of knowledge that your support staff need to know to manage the platform effectively.

On the flip side, you will have less hardware failures, as you have less hardware (yes, the impact of a failure is higher but that does not really add to the support overhead). You also have the ability to standardise your hardware a lot more, rather than having bits and bobs from hundreds of different suppliers (which will improve your ability to support the hardware).

Rapid Deployment

The final reason for virtualisation I am going to discuss is rapid (or agile) deployment, which you could, in addition, chalk down as rapid re-deployment.

The most important thing to consider here is that your ability to utilise the benefit is not really reliant on using less hardware, how much you save or even what virtualisation technology you are using but on the oft-forgotten art of planning your network architecture and design before you start building it, thinking about how the whole thing fits together and what you can gain from it.

There are a number of ways that you can gain here. The most obvious reason is the ability to move capacity around in your network or to have dark capacity that can be used for anything – all you do is install a new virtual machine and plug it in. This means you can respond quickly to changing needs by upping the capacity on a service, or redeploy capacity from value-add services into core services if you are in the middle of some disaster or another.

If you look beyond the servers and invest in a high availability Storage Area Network (SAN) then the operating system is installed onto remote storage, meaning it can be booted on any server with available capacity. This means you can move the virtual server about, upgrade it by booting it up on more powerful hardware and have it backed up (and recovered) by the storage itself – and all this from the comfort of your desk (or even your phone if your feeling up to it!).

If the ability to cope with expansion and disaster recovery is considered when you first embark upon virtualisation you can really make your network work for you.

I hope that some people have managed to read through all of that and make some sense out of it

Personally I am excited about what is now possible with virtualisation as the technology becomes more widely adopted and supported, and have enjoyed the process of learning about new technologies from scratch massively.

If I had to summarise everything I have said it would be that knowing where you want to get to when you start and planning (it sounds obvious, but you would be surprised) are the most important thing (more so even that cost, although the beanies would never agree to that). Once you have that you can tick off the pros and cons and decide whether it is the right solution for you.

We’ll start with a few of the main areas that I have come across as reasons for virtualisation:

• Saves money
• Maximises hardware utilization
• Easier to support
• Enables rapid (or agile) deployment

In all cases, these reasons can be right or wrong depending on the application of the technology. I have tried to keep this bit, as far as possible, technologically independent (meaning it can be applied to any virtualisation solution).

This week I’m only going to talk about the first one of these, Saves Money, mainly because there is a lot to say about it. This is the one that management like to see in the ‘benefits’ column of a spreadsheet and, let’s be honest, everyone likes saving money.

There are generally three areas where the cost savings from virtualisation may save you money, which are again all subject to how the technology is being used:

Hardware costs

The logic here is pretty straight forwards, if you can take a platform that would have been 10 machines and fit it onto a single server then you will have saved yourself a stack of cash.

There are other considerations here as well however. The first is would you need to buy new hardware, and effectively write off your old kit? If this is the case then you are spending money, not saving it. You may be able to mitigate this by re-using the older hardware in another application or maybe your old kit is old enough to simply write off and needs replacing. Then again, you may just need to upgrade your existing kit – a bit of extra RAM isn’t going to break the bank.

Software costs

This is more relevant to a Windows environment, where you can use virtualisation to cut out some of the expensive licensing costs on the operating System and software. On the flip side, for some licences you need to pay per-installation and the cost of software would not change and could rise.

Whether this would save you money is very application specific but is something you would need to work out when deciding whether virtualisation is for you.

Power, cooling and rack costs

As you can see, hardware and software savings are a bit pie in the sky, you can’t really say ‘that will save me money’ until you sit down and think about what you are doing in a fair amount of detail.

There is one area you are going to save money, guaranteed – your power, cooling and rack rental costs. This is the hidden vampire of the technology industry and once you progress beyond a couple of servers in a shared colo into dedicated space it really begins to bite. A shortage of power, in London especially, is forcing companies to go to great lengths to ensure they have adequate power to match their planned expansion over the next few years.

The maths is pretty simple and relates directly to how much you can virtualise.

If you can take 10 servers and consolidate them down onto a single machine then you are saving, theoretically, 90% of your power and cooling costs. This figure is probably not going to be so high, since the hardware will have a higher utilisation and therefore be closer to its peak power usage, so a more realistic figure is probably ~80%. In addition to this, your only using up one server worth of space in the datacentre so you save on your up-front infrastructure costs (installation of racks and power/cooling infrastructure).

The amount you save will depend on how much everything costs of course but let’s just look at power to start with. The first thing to note here is that these prices are going up, fast, with no indication of slowing down soon. The same global factors that push up your bills at home have an impact on the cost of commercial power, multiplied .

The cost of commercial power varies greatly depending on how much you use (think huge, shared data centre environments like Telehouse) and, when you are renting. Underlying commercial power is currently ~£0.06 per kWh when purchased is very large quantities, but the price you pay in a datacentre will include the power requirements of your cooling on top and change based on location and how good you are at contract negotiation

A price range of £0.15 to £0.30+ per kWh is a fair representation of the real cost, for a medium sized company anyway.

As a pricing example, lets take an example power cost for a small server suite, £0.25 per kWh, and a Dell 1950 specced to match those used widely here at PlusNet. This is about ~350W (0.35kW) per server so:

(server power usage in kW) x (hours in a year) x (kWh price) = (cost per annum)
0.35 x (24×365) x 0.25 = £766.50 per annum

Now if we go back to our previous example of a replacing 10 servers with 1 and reducing the energy costs by 80%, that’s a saving of over £6000 a year just on power, without taking into account the initial savings on the infrastructure and ground rent (you would need less physical space in the datacentre). This figure is an annual saving as well, adding up year on year.

As you can see, there are massive cost savings to be had from a well worked virtualisation strategy, especially for new deployments. The trick for moving an existing system over is either re-using your hardware or at least balancing the cost of new hardware against the savings you can make.

If you’ve managed to get through all that and are still interested then I’ll finish off next week by going through some of the remaining reasons why people choose to use the technology.

Virtualising the Datacentre #3 – Other Benefits of Virtualisation

For the project I have been working on for the last couple of months, consolidating all of the various backup systems around the business and bringing them together into a centralised system, I had the chance to get involved with some fairly new virtualisation software and in the process, understand a lot more about what virtualisation can and can’t do for a business.

I’ll apologise straight off the bat, I tried to make this blog a bit less technical and failed, sorry

Before we get onto the advantages and disadvantages of virtualisation, an introduction to the technology we are using that inspired this blog.

The technology chosen for the project was Solaris Logical Domain Technology (shorted to LDOM). This is not the only solution available by any means (Xen and VMWare are two popular alternatives), but it has a few advantages that swung it for us after considering the available options:

The Hardware

The current generation of Niagara processors allow for silly levels of virtualisation if necessary, and a lot of bang for your buck to boot. As an example, take a Sun 5120.

Let’s populate it with a single 1.2GHz T2 processor (64 1.2GHz processing threads, treated as individual CPU’s in the virtualised environment) and 64GB of RAM. You could partition this down to as many as 64 separate virtual machines, although more likely you choose, for example, to go for 10 very high performance virtual servers (10 CPUs and 10GB RAM with some resource left over for the underlying system).

Compare this with a Dell 1950, with a pair of 2.5GHz Inter QuadCore processors (8 2.5GHz processing threads) and you would find that it is less powerful ‘per server’, ends up using more power and costs more to buy if you want to achieve the same level of performance (note that the 1950 does have more single thread oomph).

There are more powerful alternatives available if necessary, such as the 5240, and when the much touted ‘Rock’ processor family eventually sees the light of day the available processing will only improve and the single thread processing power that the Sun kit lacks should be greatly improved.

Operating System Support

As much as Solaris as an operating system has its advantages in a number of applications, sometimes it really isn’t the right choice. Lack of a decent package management and a host of idiosyncrasies mean that a lot of the time you want to use another operating system.

Thankfully for us, then, the LDOM technology supports either Solaris or Ubuntu inside the virtual servers. This sits perfectly with the majority of systems used at PlusNet (using either Solaris 10 or Debian, which is the foundation of Ubuntu and can effectively be interchanged with only minor tweaking).

Here we see one drawback of the LDOM technology. If you were running in a Windows-centric environment its the wrong choice, same if you are tied to something like RedHat Enterprise by the software you use.

Licensing Costs

Yes, the cheapest options is not always the best … but isn’t it nice when its free! All the Logical Domain software is free and will eventually be fully Open Source (the source code for the management software, ldm, is still closed, but they are working to get this open to the community in the near future).

Data Separation

An obscure, but key, advantage of the Logical Domain technology (over, for example, Solaris Zones) is the complete separation of the virtual machines. This means that you can’t see the traffic and data in one virtual server if you manage to get access to another virtual server on the machine.

For this project we are backing up from every corner of the network, so the need to separate the backups from the servers that touch customer data (that are locked away behind extra firewalls) from backups that do not is paramount – hence the need for separation (this is a requirement of the PCI standards).

That’s about it as far as an introduction to the technology goes. If you are interested then the there is a lot more on the Sun website (although you do need a server that supports it if you want to try it!). Now we are using the platform in anger I have got to say I am impressed, with the software living up to expectations admirably.

Next week, I’ll be back to start discussing the advantages and disadvantages of virtualisation, starting with how you might be able to save your wallet.

Virtualising the Datacentre #2 – Saving with Virtualisation?

Up until now OSX has been strictly “for Macs only” (aside from hacking around getting an illegally modified version installed on a PC), but Psystar, a Miami company, announced this week of the launch of the £200 “Open PC” that is capable of running an unmodified Mac OS X 10.5 Leopard.

When you compare the configuration of the OpenPC with that of a Mac Mini you find that “the Mac Mini costs 150% of the price of the OpenPC while offering poorer performance, smaller storage space, and RAM”.

Apple ran an authorized Mac clone program for a stint of about two years in the mid-to-late 90’s, but upon Steve Jobs’ return to the business this was ceased.

Following the announcement by Psystar earlier this week, their website crashed under the load. The company said its web traffic peaked at over 30,000 hits per second on Monday, causing an outage; so there’s an undoubted demand for what they are offering.

It will be interesting to see how quickly the Apple legal team respond…

Matt Grest
Head of Future Development
PlusNet