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With them, no matter how finely he tuned his servers and storage arrays, it would basically have been first-come, first-served for packets going through his Fibre Channel switch. Like anyone who has more inbound ports than outbound ports, he wouldn't have been able to guarantee that critical apps would get the bandwidth that they needed, or conversely, that they wouldn't swamp everything else within the switch.
Baudet, who has a data networking and telecom background, opted for a new kind of storage switch developed by Sandial Systems Inc., Nashua, NH. Called the Storage Control Engine, the switch has a time division multiplexing core that provides a measure of quality of service on top of typical director-class features. Each port can be assigned a minimum and maximum time slice of the backplane bandwidth. Bandwidth can be easily reassigned on the fly to accommodate specific circumstances.
"I assign 70% of the switch bandwidth for certain apps," says Baudet. Their performance is guaranteed by the switch. Baudet says that a byproduct of the architecture is that he has
Sandial's technology is proprietary. The company has no current plans to submit it as a standard, although it hasn't ruled it out either.
This was first published in November 2003