Punkfish

Hi, I agree that the word SAN could be substituted for shared storage, however a SAN is an optimised device that will provide better performance for similiar money to a specced up server (I am obviously not advocatinh EMC, NetApp or other lagre vendors here). In the end it will just as easily come down to comfort levels with the technology, and some peole may feel more comfortabele with server based storwage than trying to take on board a new storage technologies as well as virtualisation

Hi, I do not as a rule comment on this board, but in the face of such ridiculous and ill-informed comments that I have witnessed today, I cannot help but bring my many years of virtualisation knowledge in both education and corporate world to bear. I will concede that a SAN is not technically required for virtualisation, but it should be considered as a primary component of any size virtualisation project. Not only does this system allow the flexibility to present storage dynamically based on need, but also the combined spindle count, cache and controller configuration in such a system will deliver a higher level of IOPS (which is the holy grail for virtualisation) , when compared to a stand alone systems. Almost all SANs can also host file data directly using CIFS (SMB) while at the same time using iSCSI for VM disk presentation, which will be more efficient than creating file servers in the virtual world and then saving all the file data to disks within that environment. This is in addition to the obvious benefits of "real" high availability, such as seamless failover in the event of a host failure and not having to rely on copies, most of which will only be in a “crash consistent” state, which does not guarantee a smooth failover. In regards server specifications, having a large number of servers with a small amount of RAM such as 32GB is an inefficient waste of hardware has the rest of the system will never be stretched before you run out of RAM. The whole ethos of virtualisation is to “sweat” the hardware to ensure the most cost efficient use of the investment, and buying servers like that will not accomplish this. It is best to buy say two (or three) servers with a large number of NICS to ensure sufficient bandwidth for both server and storage communication and with say 72GB RAM as a Minimum (96GB+ would be better). This type of investment is not one you make every day, and your decisions will have to stand the scrutiny of time, so make sure you have all the information at hand before making this leap, and do not fall into the all too common trap of seeing how many servers you can get for the money. Virtualisation is 90% thinking and 10% deploying, always remember to think quality before quantity and I am sure you will get the results you want.