06/13/2013
12/12/2012
09/25/2012
09/07/2012
Perceptive Load Balancing
Stingray can load balance servers in a few different ways. Looking at a Pool's Load Balancing configuration page shows the different options:
They're all pretty straightforward except for Perceptive; how does that one work? Perceptive can be thought of as Least Connections skewed to favor the servers with the Fastest Response Time. Perceptive factors in both connection counts and response times into the load balancing decision to ensure that traffic is distributed evenly amongst the servers in a farm. It is best understood in the context of a few examples:
Heterogeneous Server Farm
A great scenario in which to use Perceptive is when your server farm is heterogeneous, where some servers are more powerful than others. The challenge is to ensure that the more powerful servers get a greater share of the traffic, but that the weaker servers are not starved.
Perceptive will begin by distributing traffic based on connection counts, like Least Connections. This ensures that the weaker servers are getting traffic and not sitting idle. As traffic increases the powerful servers will naturally be able to handle it better, leading to a disparity in response times. This will trigger Perceptive to begin favoring those more powerful servers, as they are responding quicker, by giving them a greater share of the traffic.
Heterogeneous workloads
Another great scenario in which to use Perceptive is when your workload is heteregeneous, where some requests generate a lot more load on your servers than others. As in the Heterogeneous Server Farm case, Perceptive will begin by distributing traffic like Least Connections. When the workload becomes more heterogeneous, some servers will get bogged down with the more CPU intensive requests and begin to respond slower. This will trigger Perceptive to send traffic away from those servers, to the other servers that are not bogged down and responding quicker.
Summary
The Perceptive load balancing algorithm factors in both connection counts along with response times into a two step load balancing decision. When there is little disparity in response times, traffic will be distributed like Least Connections. When there is a larger disparity in response times, Perceptive will factor this in and favor the servers that are responding quicker, like Fastest Response Time. Perceptive is great for handling heterogeneity in both the server farm and the workload, ensuring effecient load balancing across your server farm in either case.
08/23/2012
08/17/2012
08/10/2012
Add a Twitter feed to your site using TrafficScript
A great usage of TrafficScipt is for managing and inserting widgets on to your site. With TrafficScript you can easily insert a Twitter Profile Widget to your site.
With a Twitter Profile Widget on your site you can easily communicate what's new, on sale, or anything else you like to your users. With TrafficScript you have ultimate control and can easily move, modify, or even disable the widget with the click of a button all within the Stingray web interface.
The TrafficScript code along with instructions is available here. Give it a try.
