[Opensim-users] Load Testing

[Robert Klein]

Excellent response Mariusz! There are many ways, as Mariusz points out, to
test our simulators. There are formal and informal methods. It really
depends on what your goals are for the test. This is generally referred to
as "starting with the end in mind". Someone who is just opening up a
nightclub on their region may only want an informal "can my region handle 80
avatars while music and video are playing?" Others may need a formal set of
replicated tests to manage their server efficiency between certain modules
compared to overall bandwidth and RAM usage. Whatever the need, proper load
testing is a big help. Maybe start coming up with a set of scripts to fill
various needs like a new bare single region, two regions, four regions,
party spot, lecture hall, etc and map out some of the formal and informal
items each needs to address?

-Robert


Mariusz Nowostawski wrote:
> 
> 
> Load testing by assembling users in an ad-hoc manner has its place, and 
> it might be a good way of keeping track of certain server-side behaviour 
> and user experiences. However, logs from such sessions are limited in 
> use, because the tests cannot be redone, and no statistics can be 
> obtained. From our experiences we have observed quite substantial 
> variations of certain load parameters with no correlation to what was 
> been actually done in a particular instance. Identifying the causes of 
> sertain bottlenecks or server behaviour is not easy, and multiple tries 
> of the same test schema with varying only few parameters are useful in 
> that regard.
> 
> 
> Generally, there are three general types of tests, that people currently 
> do on OpenSim.
> A) ad-hoc gathering of users (as prescribed above), without the ability 
> to replicate the tests or conditions, and without the ability to draw 
> statistics on the server behaviour
> B) more formal runs with real users (and real user clients) in a 
> controlled environment, where effectively the same runs can be repeated 
> over and over again to obtain statistical behaviour and identify 
> bottlenecks by controlling limited number of factors
> C) runs without real clients and without real users, where the inputs to 
> the system are generated by TestClients that "simulate" real clients - 
> these can be used as Mic Bowman explained to test various individual 
> aspects of the server performance and these are ideal for tuning those 
> isolated modules of the server
> 
> 
> Each of these has its place and role, and they all play a complementary 
> roles. At Otago, we focus primarily on B, where real clients are used to 
> test the system holistically, and investigate different 
> cross-dependencies between the server modules. I do not think Type A can 
> be formalised or automated. As for B, we tried to automate as much as 
> possible as to make the tests easier to run and manage, but, we are far 
> from NANT-like automation.  It should be possible to automate Case C, 
> and conduct multiple runs to obtain statistics in a fully automated way. 
> We are quite interested in that, and will watch where the developments 
> are heading.
> 
> 
> -- 
> cheers
> Mariusz
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> 
> 

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