On 6th Nov I wrote an article in this blog that to do virtualisation sucessfully, i use the term sucessfully as anyone can do virtualisation badly. Administrators, storage and system admins need to understand their applications before consolidating applications and servers. Historical capacity planning analysis is the only way to be able to size a new virtualisation server correctly. Well today this article appears http://www.internetnews.com/bus-news/article.php/3714351 which explains that there may not be sufficient network or I/O ports (HBA's for those in the business) on a server to cope with the capacity required by all of the virtualised servers and applications. From a storage perspective that the article refers to, it looks like people doing virtualisation have not understood the I/O profile and access patterns of the servers and applications that they are virtualising.

So everyone two choices, virtualise and hope for the best, hopefully no-one will complain as it is fashionable, a bit like the tight trousers analogy in my 6th Nov blog. The story about the emperors new clothes springs to mind. Or get out your historic capacity planning reports to see if all the applications and servers will fit together.

The process going on here is a bit like packing the car boot before going on holiday, some people fill the whole boot up with "just in case" things they may need. Others take the minimum. Some of the people that fill their cars up to the maximum never get to their destination as their suspension breaks when they hit the first bump in the road, they end up with a broken car at the side of the road. Yup they even have the roof rack filled to the brim. Overutilisation as we say. It is a comfort thing taking your house with you on holiday.

I am glad this article appeared now that the virtualisation fashion may start to calm down and people start to become more sensible. After all, it is not the first time in the IT industry that consolidating servers is a new thing, nor is server virtualisation. Maybe we are in search of something new, only to discover something old. Well for new stuff read about the coolthreads servers and X4500, in 20yrs I have never seen anyone make servers and chips that use less power and do more.