I was speaking to a client yesterday on the merits of virtualisation and what needed to be considered before moving his company ‘into the cloud’. A lot has been said in the press and by manufacturers about the benefits of hosting services, however little covers the specific problems that you are inevitably left with. In this client’s case the business was at a junction in terms of IT investment as it evaluated its creaking server infrastructure and to plan the next steps.
With eight separate servers, each carrying out a specific function it was easy to recommend sharing one larger server using something like Vmware to convert each server into a virtual environment. My word of caution came with trying to share resources between servers and better instead to over specify the base machine to ensure each server got exactly what it needed. Modern virtualisation software is clever in sharing resources but in my experience if you have a Microsoft Exchange server gobbling up 4 GB of RAM then it isn’t going to share very well with a Microsoft SQL server requiring the same. Better to ensure there is at least 8 GB on the base machine and allocated 4 to each. The same goes with processors, only hard drives can really be shared, and with RAID, reliably too. So now instead of buying eight cheap servers the client can instead buy one or two (for extra redundancy) high specification servers to carry out the same role.
The next problem is where to host the platform. While the customer knows it should be in the cloud so that it can be accessed from everywhere and highly secure it does mean handing over parts of the business to a third-party. This can be done by fully outsourcing the virtual machines and not even owning the hardware, however without full due diligence what could appear to be a good service today, could fall over when another hundred customers have the same idea. Also no SLA will ever compensate your business should the worse happen so I believe it is better plan as though everything is about to go very wrong. Therefore a good solution would be to collocate some hardware in a datacentre but also maintain a local version and replicate between the two. That way there is maximum resilience should the internet fail, supplier go bust or office burn down.
While the industry will remain very positive on the concept of the cloud it is important not to loose sight of the technical challenges your company will face and how that would impact your ability to do business.
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