Before and After Examples
Traffic example
Before using a Load Balancer
This is an example of an Alpha web application not on a load balancer and running on a single Alpha Instance. The website was in constant danger of becoming unresponsive due to heavy traffic. Here you see the traffic hitting the server at 100-150 connections per second. The black arrow at the right is where the site became so unresponsive that it was manually restarted to allow users to continue to work. Note the spike in activity just after the restart, that is users logging back in and starting up where they left off.
This application suffered in this way for several months and no re-programming remedy could be found. See the second image below once a Load Balancer was introduced.
After using a Load Balancer
After deploying a Load Balancer to spread the incoming traffic and processing over four Alpha Instance, this is how the traffic appeared (on each Instance). Note that the connections per second are packed around 60 with only a few spikes at higher rates. Note also that even though the chart covers the same time period, it looks "thinner".
The result of adding this load balancer was an INSTANT relief to the customer and we have had zero complaints about slow response ever since.
User Load example
Before using a Load Balancer
This chart is before the load balancer was added. It shows how application response time (the green line) gets significantly worse as the number of simultaneous users are increased (the blue line).Here we see that the application starts to become very laggy (16 second response time) when 12 simultaneous user are active, and tops out at 32 second response by time this test is done, around 48 simultaneous users.
Each environment is different but normally when an application fails to respond within at least ten seconds, the users begin to complain.
After using a Load Balancer
Note that as the load increases (the blue line) that the response time (the green line) stays roughly the same, about 3 seconds. This is exactly what you want!