max limit of load generators a generator can support provided the hardware

[jp]

hi All,

this sounds like vague for some but I want to know the below details

I have used load generators for 300 to 500 vuser
now I want to know how many vsuers a load generator can take
500,1000,5000
is there a limit to the load generator if any can you share it
I have used 300 to 500 vsuer at tha maximum in my projects though I
have not come across more than 1000 vusers shared acrossed load
generators or there a calculation

thanks
Jayaprakash

[James Pulley]

The problem with any estimate of such is accurately measuring how many
resources your virtual user are using. If you have a high memory bound
user, which is using 40MB per virtual user, then you have an upper limit
bound by your physical ram and the 4MB address space (before 64 bit
generators with LR 11) for how many you can get on the box. Similarly, if
you have a 300K virtual user, but one which pounds the snot out of the hard
disk subsystem then you are similarly going to have a limit of how many you
place on a box. Rule of thumb, the lighter your VU, the more per host.
Generally speaking if you have immature or poor LR developers your will be
able to get fewer vusers per host than if you have very mature performance
testers.

Short answer, at least 1, up to the limit of the resources or address space
on the host.

James Pulley, http://www.loadrunnerbythehour.com/PricingMatrix

hi All,

thanks
Jayaprakash

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[Krishnakanth PPS]

In other words.

Your number of LGs required depends on which protocol you are using and how complex is your script.

Run a 5-10-15-20-25 user test and check the CPU/Memory/Network card utilizations for the loadrunner processes on the controller machine

You should be able to arrive at a pattern and then you can arrive at a figure. 

make sure you leave a headroom of 20-30% of CPU for other processes. 

You dont want your LG machine to be a bottleneck.

[laxmi narayana]

HI,

My friend has given me a some tip on this long back.

This is how we should calculate the memory foot print.

Execute a load test for about 10 vusers. Go to Task Manager and NOTICE the memory occupied by the processes

mmdrv

LoadRunner.exe

and any other processes related to LoadRunner

if the total memory occupied by mmdrv process is say 25MB, we can say that the total memory occupied by each VUser is 25MB/10 = 2.5 MB. But to be on safer side, we usually consider it as 3 MB. This is how we should calculate the target load generated by each Load Generator.

For example if the RAM of a LG is 2 GB my calculation would be as below:

Total Ram available: 2048 MB

Memory for the OS Stuff = 100 MB

Memory for any other processes that are running on the LG = 148 MB

Total memory occupied = 248 MB

Balance Memory : 1800 MB

If each VUser takes 3 MB, maximum load that can be generated is : 1800/3 =600users

Hope this information is helpful.

Thanks,
Laxmi narayana Reddy N

[James Pulley]

It is a bit more complex than just a RAM calculation.   The performance footprint that we consider in the analysis stage consists of being bounded on Memory, Disk, Network or CPU.    Your virtual users, depending upon protocol and how they are constructed could become bound on any one (or multiple) of the above resource areas.   Here is an opportunity to exercise your analytical skills for bottleneck analysis  by monitoring your load generators and applying the same processes for bottleneck identification to your load generators as you apply to your application under test.

 

Your friend also appears to have a process issue by using the controller as a Load Generator, in addition to the control console for the test.    The front end action of the LoadRunner controller is best served by residing on a dedicated computer so the video demands of the controller activity does not distort the performance envelope/resource window for lower priority application processes, such as virtual users.    On your load generators go for blank screen savers and the lightest OS install you can manage in your environment.    If you log information, go for a co-processed disk subsystem which takes both IRQ and INT load off of your core system.   If you have a lot of Network Activity, consider the use of an intelligent network adapter with a TCPOE (TCP Offload Engine) to once again take the IRQ and INT load off of your core system.  

 

Load Generation will get a lot easier with LR 11 (Just released).   With 64 bit load generation we now have lifted the limit on RAM resources on the Load Generator beyond the 2GB (Windows Workstation) and 4GB (Windows Server) to 2^64, which hopefully we will not hit for a long time.    With the addressable RAM limit addressed we’ll very likely see the other bottleneck areas come to the forefront, DISK and NETWORK on the generator.   Sort of like squeezing one end of a balloon and observing the air bulge out the other end.

 

James Pulley, http://www.loadrunnerbythehour.com/PricingMatrix

[anita koli]

http://www.vietnamesetestingboard.org/zbxe/?mid=download&document_srl=140008&cpage=&listStyle=

 

This url will give u the information for memory usage for 1 vuser which depend on protocol.

Normally for HTTP/HTML 1GB RAM  support around 200 vuser.

Also make sure your loadrunner licence support that many number of vusers which you need to select for your scenario

 

Regards,

Anita koli

[Jaya Prakash Kolala]

Hi all,

 

thanks for the reply

 

I am getting aproject which has more than a 500 vusers with in a week so i sent this mail

 

will appriciate the help in advance as this shold be not a bottle neck

appriciate to all who replied

 

Regards

Jayaprakash

On Wed, Sep 22, 2010 at 5:37 PM, jp <prakas...@gmail.com> wrote:

[Jaya Prakash Kolala]

hi all.

 

sorry about the 500 vusers it actually more than 5000 vusers i

I donot know the exact number

will uodate you on the same

On Wed, Sep 22, 2010 at 5:37 PM, jp <prakas...@gmail.com> wrote: