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Virtual Server I/O Crisis?

Friday, 01 December 2006 by Michel Roth

Interesting article on the lack of growth in disk I/O when compared to the growth of Processor capacities. This is something that happens in SEX environments like referenced in this article but this can also easily happen in the future in high-end x64 Terminal Server systems.

"Processor performance has been on an exponential growth path for decades; however, external interface speeds haven�t accelerated at nearly the same rate. According to Schulz, network and disk are the two critical I/O paths limiting system performance. He says, �You need to be cognizant of the whole environment� when designing a virtual cluster, noting that �when you concentrate servers, think about where you have created another bottleneck.�

The key parameters to watch when characterizing I/O performance are throughput (or bandwidth) and latency. Applications that tend to have a few transactions but move large amounts of data (for example, streaming media servers) will manifest throughput bottlenecks most readily, while tasks that involve many transactions with small files (for example, email or file servers) will expose latency constraints."

Read the entire article here.