The new buzzword around the IT block is “Cloud Computing”, the ability to avoid deploying costly infrastructure on each location by contracting a “virtual” infrastructure environment from dedicated vendors. Need to expand? Just call your provider and double your server capacity and triple your storage.
However, we may need to apply a sobriety test, where are those servers? And how far out is my virtual storage? A recent article in Scientific Computing (http://www.scientificcomputing.com/articles-HPC-Cloud-Computing-Pie-in-the-sky-120109.aspx) reminds us that the flexibility of an elastic infrastructure comes with strings attached.
The author presents a case for testing adequate bandwidth, as well as measuring and testing network latency. Virtual machines can introduce additional latency through the time-sharing nature of the underlying hardware. Since the service provider — and not the scientist — control the hardware, unanticipated sharing and reallocation of machines can significantly affect runtimes.
My conclusion from this article, and others, dealing with the latency issues induced by Cloud Computing, is to include a rigorous testing phase before committing to a migration. An end to end latency measurement and emulation are probably the best ways to ensure smooth adoption of this exciting new technology.
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