Stress Testing Vs Load Testing

Load testing examines the entire environment and database, while measuring the response time, whereas stress testing focuses on identified transactions, pushing to a level so as to break transactions or systems.
System stress testing: also known as stress testing, is loading the concurrent users over and beyond the level that the system can handle, so it breaks at the weakest link within the entire system.During stress testing, if transactions are selectively stressed.
The other way of dealing this is... testing the system with heavy load & with less resources to handle.
Where as Load Testing mean to test the system with full load & with full resorces in hand.

Hits per sec & CPU

As the hits per second increases....
CPU:- Increases with increase in hits per sec

Relation between Hits Per sec, CPU Usage & Response times

As the hits per second increases....

Response times:-
1. If the application is good enough to high user load, we dont see any changes in teh response times with respect to hits per sec
2. If the application is not good enough & with performance bottlenecks then response times gradually increase with increase in hits per sec.
3. Finally if there is any network delay which occurs intemittently in some instances will increase the response times of all the transaction at that moment & hence due to which hits per sec & throughput decreases.

Relation Between Hits Per Sec & Throughput

As the hits per second increase....

Throughput:- Increases with increasing hits on the webserver for a certain range. Generally it also depends on the bandwidth available. Then at a certain range the Throughput becomes constant & at this point if hits per sec increases then the throughput decreases.

So when ever we derive a relation between Hits per sec & Throughput then with in the threshold limits they are directly proportional to each other...