The long and winding road to server virtualisation

Meanwhile, back in reality, one point that came up time and again was: remember that whatever you're doing in the virtual world, will ultimately depend on the physical world. This point manifested itself particularly in terms of getting the RAM levels right in advance, and minimizing back-end bottlenecks – that is, between the virtualized servers and whatever resources they need to access.

Management does appear to be an area of cost that hasn't yet been fully bottomed out. Tools can be expensive, and as we have seen in research, management overheads can be greater than expected particularly if you want to take advantage of all that dynamic goodness brought by virtualisation.

Load balancing VMs across your server estate is something that occupies a lot more time than I would have thought when I started using virtualisation. The more I work with it, the more I realise just how much easier this would all be if we could only afford all that stupendously expensive management software. We've managed to overcome this with some very strict procedures and a *lot* of scripts, but someone just starting out would not necessarily see a reduction in maintenance overhead. I think that if you have the real management tools to accompany virtualisation it can be a phenomenal time saver.

Unfortunately, not every IT shop is going to have the scripting skills of some of the readers (including Nate '20,000 lines of code' Amsden). And as another reader said in answer to our article on management, money for tooling is not that easy to come by:

It requires that mythical substance known as 'money'. This is something you cannot pry out of the hands of the copper-counters with a plasma rifle. No matter the business case, they seem unable to pay for any form of software based on the concept, "it saves [individual] time."

To be fair, the virtualisation wave has happened so fast, it has taken some of the traditional management tools vendors time to catch up – particularly around the management of both virtual and physical from the same console. Says Nate:

At a couple different events I've been to I've come across companies specializing in VM management, but it's rare that they can extend that expertise to physical systems as well, when I ask them their faces just go blank.

Management is about risks as well

From a production perspective, the last thing we should mention in this context is risk management – into which we can include security, disaster recovery, data protection and so on. Most respondents seem to think that virtualisation brings quite a lot to the party in terms of new options – for example snapshots can be taken of entire machines, for backup or DR purposes, and if a physical server fails, it is relatively straightforward to re-start the virtual server somewhere else. "Personally, I trust my VM backups more than my tape ones," said one enthusiastic correspondent – your own mileage may differ, particularly if you've suffered from VM proliferation and your backups haven't kept up!

On a more sober note however, perhaps we should close with the thought that virtualisation really is a two-edged sword – used incorrectly, it could cause as many problems as it solves. "Don't keep all your eggs in one basket" was the advice from more than one reader. The trick appears to be balancing the inevitable basket-ness of consolidation-by-virtualisation, with hard-earned common sense about relying too much on too few physical systems:

If you go Borg, then one virus in the main matrix blows it all. If you then say well I will start putting up Checkpoint Charlies, then you move away from consolidation and into autonomous systems anyhow.

It will always be tough to get this balance right: indeed, as we move forward with virtualisation we shall undoubtedly run into the ruts created by our own, very human traits of poor planning, inadequate investment and the vain hope that bad things only happen to other people. But be in no doubt that virtualisation is ready for prime time as a technology, even if its management ecosystem (and indeed skills base) is still evolving.

Freeform Dynamics Ltd