I am doing performance load testing in a web based application.
I learnt from JMeter Tutorial that how can I set the Ramp Up period, eg:
If 10 threads are used, and the ramp-up period is 100 seconds, then JMeter will take 100 seconds to get all 10 threads up and running. Each thread will start 10 (100/10) seconds after the previous thread was begun.
10 users, 100 seconds ramp-up - start with 1 user, each 10 seconds 1 user added
but I have one doubt can we set Ramp Up period 0 ? if yes,then How result will be affected by 0 ramp up?
Ramp up of zero (which is equivalent to 1 sec rampup) is rarely useful, except for large sites that promote release dates, ie when a new product is released at a schedule such as concert tickets or pc games.
You can use it to prove the site would cope with a sudden large influx of requests.
Likely you might also find use for a stepping ramp up, which is available from jmeter-plugins.
As others say, you are trying to simulate normal usage, so if normal usage includes sudden heavy load, keep rampup low.
However, bear in mind that with low rampup and many threads, you may be limited by local resources, so your results may be a measurement of client capability rather than server.
Look at distributed load testing, to simulate even greater loads than a single client can achieve.