Sunday, July 31, 2011

Load Balancing Without a Load Balancer

Application delivery controllers perform a great service to direct traffic to servers which should handle client requests. Decisions on where to send information can be based on a variety of factors. Like their kid brother, the server load balancer, they present a virtual service address, linked to more than one backend system. By monitoring services on individual servers, the ADC or SLB drops unreliable services from pools to ensure high availability. Further, they divvy requests between servers which can answer them, balancing a load which might be higher than one system could accept.

There are times when you don't need the delivery options an ADC can provide, and even an SLB solution might not make sense. A tandem set of appliances for each local area network where servers reside is expensive to purchase and maintain vendor support. They also require power and use precious rack space. If a server load balancer is all you need to ensure service availability while dividing load, perhaps a different solution could do the job.

Wednesday, July 13, 2011

A Ride Over The Bridge And Back

Wonderful weather last Saturday, so I took the train into San Francisco and decided to ride my bicycle around the city. Starting close to AT&T Park, I rode down the Embarcadero, along the beach, and then over the Golden Gate Bridge. Turning back, I went through the city streets a bit more, through Chinatown and around Russian Hill, before heading back to the Caltrain.